Vista - SigmaTel High Definition Audio Codec

Hello! Possible bug follows:

I just recently installed RC1 and it was pretty smooth--except for the
sound. While it runs mostly out of the box and I can not record anything
using my microphone. At first it used some generic driver (Microsoft High
Defintion Audio.. something like that) and after fiddling with it I think I
was able to get it to use the updated driver from Windows Update to stick
(did a Roll Back and after refreshing a couple of times it seemingly went
back to the SigmaTel driver). Well sure its using the new one (I hope >_>)
but nothing shows up Recording section. Somehow no audio devices are
installed.

Any suggestions?

General Computer Specs:
Gateway 840GM; Intel 945G (intergrated sound); Windows Vista RC1 (Build 5600)