Make Homosexuality an issue of constant discussion. At gatherings of ministers, in your publications, at coffee breaks, and on the floor of all legislative sessions keep bringing it up. It doesn't even matter which way the discussion goes. Just bringing it up helps your cause. This other side will agree with you, or at least be closer to you.
Inflexible positions erode gradually.
No position changes without discussion. The more you discuss it, the sooner the change. In fact, even this article may help you. Recruit a prominent ally. Try to get a prominent evangelical to speak out for your side.