I don't know why it WOULDN'T work, aside from the fact that the Mac uses EFI, and needs video cards with EFI firmwares; and some cards do not have EFI firmware, just old-fashioned VGA BIOSes.
As long as the card has an EFI firmware AND a VGA BIOS, it should work just fine on the Windows side. (EFI so the Mac will initialize it, VGA so Windows can talk to it. One of the things Boot Camp does is fake a VGA BIOS for Windows' benefit.)
And, please, please, use at least semi-proper grammar and spelling... From your spelling, I would assume that you are a native German speaker with little English knowledge. (If it's true, fine, but if you're a native English speaker, come on... Use spell check at least.)