My web application has (server side) a wav file saved using truespeech and then a client (ie6, ie7) can ask to plat the file and the web server serves it..

All you need on xp is to have WMP 9 or higher and it all works. but on vista.. suddenly the vista client box can't play the file cause it doesn't support truespeech (some upgrade!)

anyone has an idea of what should I do?

1. You can suggest a way to make it work on the client (but in general, I don't like having to say that the solution includes installing anything on the client box)
2. you can suggest I don't save the server side file in truespeech, and instead use something else (what?)