EXHIBIT 99.12

                                PAYMENT GUARANTY
                                ----------------
                             (Principal Shareholder)


            This Payment  Guaranty (this  "GUARANTY") is made as of February 11,
2003, by John W. Burcham II ("GUARANTOR"),  in favor of MERCATOR ADVISORY GROUP,
LLC,  acting as agent (in such  capacity,  "AGENT") for MERCATOR  MOMENTUM FUND,
L.P., and MECATOR FOCUS FUND, L.P. (each, a "LENDER" and, together,  "LENDERS").
Mercator is acting  hereunder  for the benefit of the Lenders on a  proportional
basis in accordance with the amounts of their respective  interests in the Loan,
as that term is defined below.

                               FACTUAL BACKGROUND
                               ------------------

      A.    Guarantor is executing  this Guaranty to induce  Lenders to make two
separate  loans  (defined,  together,  in SECTION 2 as the  "LOAN") to  MediaBus
Networks, Inc., a Florida corporation,  and Presidion Solutions, Inc., a Florida
corporation  (each, a "BORROWER" and, together,  "BORROWERS"),  in the aggregate
principal amount of Two Million Dollars ($2,000,000.00).

      B.    Concurrently  herewith,  Guarantor is executing a document  entitled
Pledge Agreement in favor of Agent (the "PLEDGE  AGREEMENT") to provide security
for the obligations of Guarantor under this Guaranty.

      C.    The Loan is evidenced by 6-1/2%  Secured  Convertible  Debentures of
even date herewith (the "DEBENTURES"),  each made payable to one of the Lenders,
which, together, are in the principal amount of the Loan.

      D.    This Guaranty,  the Pledge  Agreement,  the Debentures and all other
documents  executed by either Guarantor or Borrowers in connection with the Loan
are referred to herein as the "LOAN DOCUMENTS."

                                    GUARANTY
                                    --------

            1.  GUARANTY OF LOAN. Guarantor unconditionally guarantees to Agent,
for the benefit of Lenders,  the full payment of the Loan,  and  unconditionally
agrees to pay Agent the full amount of the Loan.  This is a guaranty of payment,
not of  collection.  If Borrowers  default in the payment when due of all or any
part of the Loan,  Guarantor  shall in lawful money of the United  States pay to
Agent or order,  on demand,  all sums due and owing on the Loan,  including  all
interest, charges, fees and other sums, costs and expenses.

            2.  LOAN. In this  Guaranty,  the term "LOAN" is broadly  defined to
mean and include all primary, secondary,  direct, indirect, fixed and contingent
obligations  of Borrowers to pay  principal,  interest,  prepayment  fees,  late
charges,  loan fees and any other fees, charges,  sums, costs and expenses which
may be owing at any time  under  either  of the  Debentures  or the  other  Loan
Documents,  as any or all of them may from  time to time be  modified,  amended,
extended or renewed. If the amount outstanding under the Loan is determined by a
court of competent  jurisdiction,  that  determination  shall be conclusive  and
binding on Guarantor,  regardless of whether or not Guarantor was a party to the
proceeding in which the determination was made.

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            3.  RIGHTS OF AGENT.  Guarantor  authorizes  Agent and each  Lender,
acting  separately or together,  to perform any or all of the following  acts at
any time in its sole  discretion,  all without  notice to Guarantor  and without
affecting Guarantor's obligations under this Guaranty:

                (a)  Lenders  may alter any terms of the Loan or any part of it,
including  renewing,  compromising,  extending  or  accelerating,  or  otherwise
changing  the time for  payment  of, or  increasing  or  decreasing  the rate of
interest on, the Loan or any part of it.

                (b) Lenders and Agent may take and hold security for the Loan or
this  Guaranty,  accept  additional  or  substituted  security  for either,  and
subordinate,  exchange, enforce, waive, release, compromise, fail to perfect and
sell or otherwise dispose of any such security.

                (c)  Lenders  and Agent may  direct  the order and manner of any
sale of all or any part of any  security now or later to be held for the Loan or
this Guaranty, and Lender may also bid at any such sale.

                (d) Lenders and Agent may apply any payments or recoveries  from
Borrowers,  Guarantor or any other source, and any proceeds of any security,  to
Borrower's  obligations  under  the Loan  Documents  in such  manner,  order and
priority  as Lenders or Agent may elect,  whether or not those  obligations  are
guaranteed by this Guaranty or secured at the time of the application.

                (e)  Lenders  may release  either or both  Borrowers  from their
liability for the Loan or any part of it.

                (f) Lenders and Agent may substitute,  add or release any one or
more guarantors or endorsers.

                (g) In addition to the Loan,  Lenders may extend other credit to
Borrowers,  and may take and hold  security  for the  credit  so  extended,  all
without affecting Guarantor's liability under this Guaranty,  provided that this
Guaranty does not apply to such other credit.

            4.  GUARANTY TO BE ABSOLUTE.  Guarantor  expressly agrees that until
the Loan is paid and  performed  in full and each and every term,  covenant  and
condition of this Guaranty is fully  performed,  Guarantor shall not be released
by or because of:

                (a) Any act or event which might  otherwise  discharge,  reduce,
limit or modify Guarantor's obligations under this Guaranty;

                (b) Any waiver, extension,  modification,  forbearance, delay or
other act or  omission  of Agent or any  Lender,  or their  failure  to  proceed
promptly or otherwise as against Borrowers, Guarantor or any security;

                (c) Any action,  omission or  circumstance  which might increase
the likelihood  that Guarantor may be called upon to perform under this Guaranty
or which might affect the rights or remedies of Guarantor as against Borrowers;

                                      -2-


                (d) Any dealings  occurring  at any time between  either or both
Borrowers and Agent or either or both Lenders,  whether  relating to the Loan or
otherwise; or

                (e) Any  action of Agent or any  Lender  described  in SECTION 3
above.

            Guarantor hereby  acknowledges that absent this SECTION 4, Guarantor
might have a defense to the  enforcement  of this Guaranty as a result of one or
more of the foregoing acts, omissions, agreements, waivers or matters. Guarantor
hereby  expressly  waives and surrenders any defense to any liability under this
Guaranty based upon any of such acts, omissions, agreements, waivers or matters.
It is the express intent of Guarantor that  Guarantor's  obligations  under this
Guaranty are and shall be absolute, unconditional and irrevocable.

            5.  GUARANTOR'S WAIVERS. Guarantor waives:


                (a) Any right  Guarantor may have to require Agent or Lenders to
proceed against any Borrower,  proceed against or exhaust any security held from
any  Borrower,  or pursue any other remedy in Agent's or any  Lender's  power to
pursue;

                (b) Any defense based on any claim that Guarantor's  obligations
exceed or are more burdensome than those of any Borrower;

                (c) Any  defense  based  on:  (i) any  legal  disability  of any
Borrower, (ii) any release, discharge, modification, impairment or limitation of
the liability of any Borrower to any Lender from any cause, whether consented to
by any Lender or arising by  operation  of law or from any  bankruptcy  or other
voluntary or involuntary  proceeding,  in or out of court, for the adjustment of
debtor-creditor  relationships ("INSOLVENCY PROCEEDING") and (iii) any rejection
or disaffirmance of the Loan, or any part of it, or any security held for it, in
any such Insolvency Proceeding;

                (d) Any  defense  based on any  action  taken or  omitted by any
Lender  in  any  Insolvency  Proceeding  involving  either  or  both  Borrowers,
including  any election to have any Lender's  claims  allowed as being  secured,
partially  secured or  unsecured,  any  extension of credit by any Lender to any
Borrower in any  Insolvency  Proceeding,  and the taking and holding by Agent or
any Lender of any security for any such extension of credit;

                (e)  All  presentments,  demands  for  performance,  notices  of
nonperformance,  protests,  notices of protest, notices of dishonor,  notices of
acceptance of this Guaranty and of the  existence,  creation or incurring of new
or additional indebtedness, and demands and notices of every kind;

                (f) Any defense  based on or arising out of any defense that any
Borrower may have to the payment or  performance  of the Loan or any part of it,
other than the defense that the Loan has been paid in full; and

                (g) Any  defense  based on or arising out of any action of Agent
or any Lender described in SECTIONS 3 OR 4 above.

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            6.  WAIVERS OF SUBROGATION AND OTHER RIGHTS AND DEFENSES.


                (a) Upon a default by Borrowers,  Agent, Lenders or an agent for
any such  person,  in its sole  discretion,  without  prior notice to (except as
required by applicable law) or consent of Guarantor, may elect to: (i) foreclose
either  judicially  or  nonjudicially  against  any  real or  personal  property
security it may hold for the Loan,  (ii) accept a transfer of any such  security
in lieu of foreclosure, (iii) compromise or adjust the Loan or any part of it or
make any other accommodation with either or both Borrowers or Guarantor, or (iv)
exercise any other remedy  against any Borrower or any security.  No such action
by Agent or either  Lender  shall  release or limit the  liability  of Guarantor
(except to the extent the Loan is satisfied or reduced as a result thereof), who
shall remain liable under this Guaranty after the action,  even if the effect of
the  action  is to  deprive  Guarantor  of any  subrogation  rights,  rights  of
indemnity,  or other rights to collect  reimbursement  from any Borrower for any
sums paid to Agent or any Lender, whether contractual or arising by operation of
law or otherwise.  Guarantor  expressly agrees that under no circumstances shall
he be deemed to have any right,  title,  interest  or claim in or to any real or
personal  property to be held by Agent or either Lender or any third party after
any foreclosure or transfer in lieu of foreclosure of any security for the Loan.

                (b)  Regardless of whether  Guarantor may have made any payments
to Agent or any Lender,  Guarantor hereby waives: (i) all rights of subrogation,
indemnification, contribution and any other rights to collect reimbursement from
any  Borrower  or any other  party for any sums paid to Agent or either  Lender,
whether  contractual or arising by operation of law (including the United States
Bankruptcy  Code or any  successor or similar  statute) or  otherwise,  (ii) all
rights to enforce  any remedy  that  Agent or any  Lender may have  against  any
Borrower, and (iii) all rights to participate in any security now or later to be
held by Agent or any Lender for the Loan.  The waivers given in this  SUBSECTION
6(B) shall be effective until the Loan has been paid and performed in full.

                (c)  Guarantor  further  waives any  defense to the  recovery by
Agent or any Lender  against  Guarantor  of any  deficiency  or otherwise to the
enforcement  of this  Guaranty  or any  security  for this  Guaranty  based upon
Agent's  or  any  Lender's  election  of any  remedy  against  Guarantor  or any
Borrower.

                (d) Guarantor waives any rights,  defenses and benefits that may
be derived from Sections 2787 to 2855,  inclusive,  of the California Civil Code
or  comparable  provisions  of the laws of any other  jurisdiction  and  further
waives all other  suretyship  defenses  Guarantor would otherwise have under the
laws of California or any other jurisdiction.

                (e) No provision or waiver in this  Guaranty  shall be construed
as limiting the  generality of any other  provision or waiver  contained in this
Guaranty.  All of the waivers contained herein are irrevocable and unconditional
and are intentionally and freely made by Guarantor.

            7.  REVIVAL AND REINSTATEMENT. If Agent or any Lender is required to
pay,  return  or  restore  to any  Borrower  or any  other  person  any  amounts
previously paid on the Loan because of any Insolvency Proceeding of any Borrower
or any other  reason,  the  obligations  of Guarantor  shall be  reinstated  and

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revived and the rights of Agent and Lenders  shall  continue with regard to such
amounts, all as though they had never been paid.

            8.  INFORMATION  REGARDING BORROWERS.  Before signing this Guaranty,
Guarantor  investigated  the  financial  condition  and business  operations  of
Borrowers  and such other  matters as  Guarantor  deemed  appropriate  to assure
himself  of  Borrowers'  ability to  discharge  its  obligations  under the Loan
Documents. Guarantor assumes full responsibility for that due diligence, as well
as for keeping  informed of all matters which may affect  Borrowers'  ability to
pay and perform their obligations to Lenders.  Agent and Lenders have no duty to
disclose  to  Guarantor  any  information  which any of them may have or receive
about Borrowers'  financial condition or business  operations,  the condition or
uses of any properties of any Borrower,  or any other  circumstances  bearing on
Borrowers' ability to perform.

            9.  SUBORDINATION.  Any rights of Guarantor, whether now existing or
later  arising,  to receive  payment on account of any  indebtedness  (including
interest) owed to Guarantor by either Borrower,  or to withdraw capital invested
by  Guarantor  in either  Borrower,  or to  receive  distributions  from  either
Borrower,  shall at all times be  subordinate as to lien and time of payment and
in all other  respects to the full and prior  repayment  to Lenders of the Loan.
Guarantor shall not be entitled to enforce or receive payment of any sums hereby
subordinated  until  the Loan has been paid and  performed  in full and any such
sums  received in violation of this  Guaranty  shall be received by Guarantor in
trust for Agent. The foregoing  notwithstanding,  if Guarantor provides services
to either  Borrower,  Guarantor  is not  prohibited  from  receiving  reasonable
compensation from Borrowers.

            10. EVENTS OF DEFAULT.  Agent may declare Guarantor to be in default
under this Guaranty upon the occurrence of any of the following  events ("EVENTS
OF DEFAULT"):

                (a) Guarantor  fails to perform  Guarantor's  obligations  under
SECTION 1 of this Guaranty; or

                (b)  Guarantor  fails to perform or comply with any  covenant or
agreement  contained in this Guaranty  (other than those  referred to in SECTION
10(A)),  provided, that if such failure is by its nature capable of being cured,
then such  failure  shall not become an Event of  Default  unless  such  failure
remains  uncured  for a period  ending on the first to occur of thirty (30) days
after  Guarantor shall receive written notice of any such failure from Lender or
thirty  (30) days after  Guarantor  became  aware or should  have  become  aware
thereof; or

                (c) Guarantor  revokes this  Guaranty or this  Guaranty  becomes
ineffective for any reason; or

                (d) Any representation or warranty made or given by Guarantor to
Agent or either Lender proves to be false or misleading in any material respect;
or

                (e) Guarantor (i) shall become insolvent or shall generally not,
or shall be unable to, or shall admit in writing  Guarantor's  inability to, pay
Guarantor's  debts as they come due;  or (ii) shall make an  assignment  for the
benefit of creditors;  or (iii) shall apply for, consent to, or acquiesce in the
appointment  of a  trustee,  receiver,  or  custodian  for  Guarantor  or any of


                                      -5-


Guarantor's property; or (iv) shall commence or have commenced against Guarantor
any proceeding under any bankruptcy,  reorganization,  arrangement, readjustment
of debt, dissolution or liquidation law or statute of any jurisdiction.

            11. AUTHORIZATION; NO VIOLATION. Guarantor is authorized to execute,
deliver and perform under this Guaranty, which is a valid and binding obligation
of Guarantor. No provision or obligation of Guarantor contained in this Guaranty
violates any applicable law, regulation or ordinance,  or any order or ruling of
any court or  governmental  agency.  No such  provision or obligation  conflicts
with, or constitutes a breach or default under, any agreement to which Guarantor
is a party. No consent,  approval or authorization of or notice to any person or
entity is required in connection with  Guarantor's  execution of and obligations
under this Guaranty.

            12. ADDITIONAL AND INDEPENDENT OBLIGATIONS.  Guarantor's obligations
under this Guaranty are in addition to Guarantor's  obligations  under any other
existing  or future  guaranties,  each of which  shall  remain in full force and
effect until it is expressly  modified or released in a writing signed by Agent.
Guarantor's  obligations  under  this  Guaranty  are  independent  of  those  of
Borrowers on the Loan. Agent may bring a separate action, or commence a separate
reference or arbitration  proceeding  against Guarantor without first proceeding
against either  Borrower,  any other person or any security that Agent or either
Lender may hold,  and without  pursuing any other remedy.  Agent's  rights under
this  Guaranty  shall not be exhausted  by any action by Agent or either  Lender
until the Loan has been paid and performed in full.

            13. NO WAIVER;  CONSENTS;  CUMULATIVE REMEDIES. Each waiver by Agent
must be in writing,  and no waiver shall be construed as a continuing waiver. No
waiver shall be implied from Agent's or either  Lender's  delay in exercising or
failure to exercise  any right or remedy  against  Borrowers,  Guarantor  or any
security.  Consent by Agent or either Lender to any act or omission by Borrowers
or Guarantor  shall not be construed as a consent to any other or subsequent act
or  omission,  or as a waiver of the  requirement  for  Agent's or any  Lender's
consent to be obtained in any future or other  instance.  All  remedies of Agent
and Lenders against Borrowers and Guarantor are cumulative.

            14. NO RELEASE. Guarantor shall not be released from his obligations
under this Guaranty except by a writing signed by Agent.

            15. HEIRS,  SUCCESSORS AND ASSIGNS;  DISCLOSURE OF INFORMATION.  The
terms of this Guaranty shall bind and benefit the heirs, legal  representatives,
successors  and  assigns  of  Lender  and  Guarantor;  provided,  however,  that
Guarantor may not assign this Guaranty,  or assign or delegate any of his rights
or obligations  under this Guaranty,  without the prior written consent of Agent
in each  instance.  Agent and any Lender  may,  at any time,  sell,  transfer or
assign all or any  portion of the Loan and the Loan  Documents.  In the event of
any such sale,  transfer  or  assignment  of the Loan or any part  thereof,  the
rights and benefits  under this Guaranty,  to the extent  applicable to the Loan
obligations  so sold,  transferred  or assigned,  may be  transferred  with such
obligations.  Guarantor waives notice of any sale, transfer or assignment of the
Loan and/or this Guaranty or any part  thereof,  and agrees that failure to give
notice of any such sale, transfer or assignment will not affect the liability of
Guarantor  hereunder.  Agent and each Lender is hereby authorized to disseminate


                                      -6-


any information it now has or hereafter  obtains  pertaining to the Loan or this
Guaranty,  including credit or other information on Borrowers,  Guarantor and/or
any party  liable,  directly  or  indirectly,  for any part of the Loan,  to any
actual or  prospective  assignee with respect to the Loan, to any  affiliates or
Agent or  Lenders,  to any  regulatory  body having  jurisdiction  over Agent or
either  Lender,  and to any other parties as necessary or appropriate in Agent's
or  either   Lender's   reasonable   judgment.   The  Lenders  are  third  party
beneficiaries of this Payment Guaranty.

            16. NOTICES.  All  notices  given  under  this  Guaranty  must be in
writing and shall be effectively  served upon delivery,  or if mailed,  upon the
first to occur of receipt or the expiration of  forty-eight  hours after deposit
in certified  United  States mail,  postage  prepaid,  sent to the party at such
party's  address  given  at the end of this  Guaranty.  Those  addresses  may be
changed by Agent or Guarantor by written notice to the other party.

            17. RULES OF  CONSTRUCTION.  In this Guaranty,  the word "BORROWERS"
includes  both the named  Borrowers and any other person who at any time assumes
or otherwise  becomes primarily liable for all or any part of the obligations of
the named  Borrowers on the Loan.  The word  "PERSON"  includes any  individual,
company,  trust or other legal entity of any kind. The word  "INCLUDE(S)"  means
"include(s), without limitation," and the word "INCLUDING" means "including, but
not limited to." When the context and construction so require, all words used in
the singular shall be deemed to have been used in the plural and vice versa.  No
listing of specific  instances,  items or matters in any way limits the scope or
generality  of any language of this  Guaranty.  All  headings  appearing in this
Guaranty are for  convenience  only and shall be disregarded in construing  this
Guaranty.

            18. GOVERNING LAW. This Guaranty shall be governed by, and construed
in accordance with, the laws of the State of California.

            19. COSTS AND EXPENSES. If any lawsuit,  reference or arbitration is
commenced  which  arises  out of, or which  relates to this  Guaranty,  the Loan
Documents or the Loan,  the  prevailing  party shall be entitled to recover from
each other party such sums as the court, referee or arbitrator may adjudge to be
reasonable attorneys' fees in the action or proceeding, in addition to costs and
expenses  otherwise  allowed  by law.  In all other  situations,  including  any
Insolvency Proceeding,  Guarantor agrees to pay all of the costs and expenses of
Agent and Lenders, including attorneys' fees which may be incurred in any effort
to collect or enforce  the Loan or any part of it or any term of this  Guaranty.
From the time(s) incurred until paid in full to Agent and Lender, all sums shall
bear interest at the rate of interest for the Loan specified in the Debentures.

            20. CONSIDERATION.  Guarantor acknowledges that Guarantor expects to
benefit from Lenders  extension of the Loan to Borrowers  because of Guarantor's
relationship  to  Borrowers,  and that  Guarantor is executing  this Guaranty in
consideration of that anticipated benefit.

            21. INTEGRATION;   MODIFICATIONS.   This  Guaranty  and  the  Pledge
Agreement (a) integrate all the terms and conditions  mentioned in or incidental
to this Guaranty and the Pledge  Agreement,  (b) supersede all oral negotiations
and prior writings with respect to their subject matter, and (c) are intended by
Guarantor and Agent as the final expression of the agreement with respect to the
terms and conditions set forth in this Guaranty and the Pledge  Agreement and as


                                      -7-


the complete  and  exclusive  statement of the terms agreed to by Guarantor  and
Agent.  No  representation,   understanding,   promise  or  condition  shall  be
enforceable  against any party hereto unless it is contained in this Guaranty or
the Pledge  Agreement.  This  Guaranty  may not be modified  except in a writing
signed by both Agent and Guarantor.  No course of prior dealing, usage of trade,
parol or extrinsic evidence of any nature shall be used to supplement, modify or
vary any of the terms hereof.

            22. MISCELLANEOUS. The illegality or unenforceability of one or more
provisions of this Guaranty shall not affect any other provision.  This Guaranty
and any attached  consents or exhibits  requiring  signatures may be executed in
counterparts,  and all  counterparts  shall  constitute  but  one  and the  same
document.  Time  is of the  essence  in the  performance  of  this  Guaranty  by
Guarantor.

            23. COUNSEL.  Guarantor acknowledges that Guarantor has had adequate
opportunity  to carefully  read this Guaranty and to consult with an attorney of
Guarantor's choice prior to signing it.


            IN WITNESS  WHEREOF,  Guarantor has executed this Guaranty as of the
date first above written.

Guarantor: John W. Burcham II              Address Where Notices to
                                           Guarantor are to be Sent:
    /s/ John W. Burcham II
- -----------------------------              775 W. Big Beaver, Ste. 1700,
    Signature of Guarantor                 Troy, MI 48084

       John W. Burcham II
- -----------------------------
   Printed Name of Guarantor
                                           Address Where Notices to
                                           Agent to be Sent:

                                           Mercator Advisory Group, LLC
                                           555 South Flower Street, Suite 4500
                                           Los Angeles, California 90071



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