EXHIBIT 99(a) EVERY SHAREHOLDER'S VOTE IS IMPORTANT YOUR PROXY VOTE IS IMPORTANT! AND NOW YOU CAN VOTE YOUR PROXY ON THE PHONE OR THE INTERNET. IT SAVES MONEY! TELEPHONE, FACSIMILE AND INTERNET VOTING SAVES POSTAGE COSTS. SAVINGS WHICH CAN HELP MINIMIZE EXPENSES. IT SAVES TIME! TELEPHONE AND INTERNET VOTING IS INSTANTANEOUS - 24 HOURS A DAY. IT'S EASY! JUST FOLLOW THESE SIMPLE STEPS: 1. READ YOUR PROXY STATEMENT AND HAVE IT AT HAND. 2. CALL TOLL-FREE 1-866-241-6192, OR GO TO WEBSITE: HTTPS://VOTE.PROXY-DIRECT.COM 3. FOLLOW THE RECORDED OR ON-SCREEN DIRECTIONS. 4. DO NOT MAIL YOUR PROXY CARD WHEN YOU VOTE BY PHONE, OR INTERNET. Please detach at perforation before mailing. PROXY PROXY JOINT SPECIAL MEETING OF SHAREHOLDERS TO BE HELD ON SEPTEMBER 23, 2005 The undersigned holder of shares of beneficial interest, par value $0.01 per share, of Van Kampen Advantage Municipal Income Trust (the "Fund"), hereby appoints John L. Sullivan, Lou Anne McInnis and Elizabeth A. Nelson and each of them or their respective designees, with full power of substitution and revocation, as proxies to represent the undersigned at the joint special meeting of shareholders to be held at the offices of Van Kampen Investments Inc., One Parkview Plaza, Oakbrook Terrace, Illinois 60181-5555 on September 23, 2005 at 10:00 a.m., and any adjournments thereof (the "Meeting"), and thereat to vote all shares of beneficial interest which the undersigned would be entitled to vote, with all powers the undersigned would possess if personally present, in accordance with the instructions indicated herein. If more than one of the proxies, or their substitutes, are present at the Special Meeting or any adjournment thereof, they jointly (or, if only one is present and voting, then that one) shall have authority and may exercise all powers granted hereby. THE UNDERSIGNED HEREBY ACKNOWLEDGES RECEIPT OF THE ACCOMPANYING NOTICE OF JOINT SPECIAL MEETING OF SHAREHOLDERS AND JOINT PROXY STATEMENT/PROSPECTUS FOR THE MEETING TO BE HELD ON SEPTEMBER 23, 2005 AT X:XX A.M. THIS PROXY IS SOLICITED ON BEHALF OF THE FUND'S BOARD OF TRUSTEES. VOTE VIA THE TELEPHONE: 1-866-241-6192 VOTE VIA THE INTERNET: HTTPS://VOTE.PROXY-DIRECT.COM 999 9999 9999 999 NOTE: Please sign exactly as your name appears on this proxy card. All joint owners should sign. When signing as executor, administrator, attorney, trustee or guardian or as custodian for a minor, please give full title as such. If a corporation, please sign in full corporate name and indicate the signer's office. If a partner, sign in the partnership name. -------------------------------------- Signature -------------------------------------- Signature (if held jointly) -------------------------------------- Date XXX XXXX EVERY SHAREHOLDER'S VOTE IS IMPORTANT PLEASE SIGN, DATE AND RETURN YOUR PROXY TODAY Please detach at perforation before mailing. This proxy, when properly executed, will be voted in accordance with the instructions marked hereon by the Shareholder signing this proxy. IF NO SPECIFICATION IS MADE, THIS PROXY WILL BE VOTED "FOR" THE PROPOSALS DESCRIBED HEREIN AND IN THE DISCRETION OF THE PROXIES UPON SUCH OTHER BUSINESS AS MAY PROPERLY COME BEFORE THE MEETING AND ANY AND ALL ADJOURNMENTS THEREOF. THE BOARD OF TRUSTEES RECOMMENDS THAT YOU VOTE FOR THE PROPOSALS. PLEASE MARK VOTES AS IN THIS EXAMPLE: [X] FOR AGAINST ABSTAIN 1. To approve an Agreement and Plan of Reorganization [ ] [ ] [ ] between the Fund and the Van Kampen Municipal Opportunity Trust, the termination of the Fund's registration under the Investment Company Act of 1940, as amended, and the dissolution of the Fund under applicable state law; 2. Not applicable to the Fund; 3. To transact such other business as may properly be presented at the Meeting or any adjournment thereof. THE BOARD OF TRUSTEES OF THE FUND REQUESTS THAT YOU VOTE YOUR SHARES BY INDICATING YOUR VOTING INSTRUCTIONS ON THIS PROXY CARD, DATING AND SIGNING SUCH PROXY CARD AND RETURNING IT IN THE ENVELOPE PROVIDED, WHICH IS ADDRESSED FOR YOUR CONVENIENCE AND NEEDS NO POSTAGE IF MAILED IN THE UNITED STATES, OR BY RECORDING YOUR VOTING INSTRUCTIONS BY TELEPHONE OR VIA THE INTERNET. XXX XXXX