A vibrant user community will almost always give you quicker response than the manufacturer. You know MS would charge a fortune for detailed personal support, if they had a solution.... Be happy that Apple has a lot of enthusiastic users.
Did you see [link|http://discussions.apple.com/search.jspa?objID=c235&search=Go&q=vista+share|these threads] in Apple's forums regarding sharing with Vista?
If you must have Windows, [link|http://www.simplehelp.net/2007/02/10/how-to-install-vista-in-os-x-using-parallels-a-complete-walkthrough/|Parallels] is an option you might consider while these issues are being resolved.
HTH! Good luck.
Cheers,
Scott.