I wouldn't hold out much hope, just because of the tightened security. That being said, Vista allows you to run applications in what amounts to an emulation mode of older operating systems (95, 98, 2000, XP, etc.). Perhaps that would be the way to go.
However, if the budget permits, bring on in house to test, test, and test before releasing it into wilds of normal user land. Given enough time to test and tweak, you may find a way of making it work.