Windows 8 on 2012 Mac Mini with Bootcamp 5 - high def audio not working?

Hi,

I have a 2012 Mac Mini that I installed Windows 8 with using the pre 10.8.3 bootcamp (version 4). All drivers worked except the Realtek High Definition Audio device driver that I assume is the audio component of my HDMI ports. In device manager the comment was "This device cannot start" (Code 10) and the detailed incident log recorded this info:

Driver Management has concluded the process to add Service HdAudAddService for Device Instance ID HDAUDIO\FUNC_01&VEN_8086&DEV_2806&SUBSYS_80860101&REV_1000\4&173B8F67&0&0301 with the following status: 0.

Driver Management concluded the process to install driver hdaudio.inf_amd64_5b0eb832dc5083c5\hdaudio.inf for Device Instance ID HDAUDIO\FUNC_01&VEN_8086&DEV_2806&SUBSYS_80860101&REV_1000\4&173B8F67&0&0301 with the following status: 0x0.

I assumed this error was just because Bootcamp 4 didn't support Windows 8 but I have since uninstalled the device in device manager and reinstalled the Bootcamp 5 drivers over the top and get the same error. Is it just that I did things in the wrong order and need to reinstall Windows 8 fresh and then install the Bootcamp 5 drivers or is there another issue at play here?

Cheers in advance!