ALC888 soundcard invisible?

I can't install the beta Vista drivers from the Realtek website for my ALC888
onboard audio because of the apparently classic missing Microsoft HD "bus
driver" error (AKA the Microsoft UAA - Universal Audio Architecture driver).
I've scoured the net searching for help and can only find solutions for XP or
2003 server. One would think that the Vista driver would SOMEHOW install in
VISTA. Contributing to my setback is the fact that the soundcard doesn't
even appear in device manager. There are no unknown devices and no question
marks in ANY of the branches. The soundcard works fine in my XP boot so it's
not a hardware problem. Any help in fixing this problem would be greatly
appreciated. Thanks.