My Win8 install on 2011 MacMini experience - Two issues remaining. Anyone?

Using Bootcamp v5.0.2 (462) I just installed Windows 8 on my 2011 MacMini (OSX 10.8.3; Intel HD Graphics 3000 version). The installation by itself was a breeze and everything is working fine except two issues:

1) My magic mouse is largely working (including scrolling) but very often gets 'stuck' for 5-10 seconds (per every 10-20 seconds of use). The bluetooth drivers seems to be installed ok as my Apple keyboard is working 99% fine. Is this fixable? Or native to the current Apple drivers? In MacOS the magic mouse works just fine.

2) For the life of me, I can't get the HDMI sound output to work; I just get stereo. I have an HDMI cable going from my MacMini to my HK AVR7550HD which is again sending video to my Plasma panel using HDMI. In the Device Manager, under 'Sound, video and game controllers', is listed Cirrus Logic CS4206B and High Definition Audio Device (the latter with a yellow warning icon). When I pull up the Properties of the High Definition Audio Device it shows "This device cannot start (Code 10)". I already tried repairing the Bootcamp drivers and reinstalled the CirrusAudio64 driver. But no luck.

I could possibly live with the stuck mouse for a while but not with the just stereo sound.

Does anyone has a suggestion, or even better, the solution? Many thanks!