I did end up getting it going actually. Oddly it wasn't in the soundcard setup/drivers. I tried setting the audio output in TMT to 5.1 - which would make sense to me - and that didn't work but setting it to SPDIF did get the 5.1 working eventhough it was already using the SPDIF as the output anyway and the soundcard setting still says 2 channel. No wonder I had trouble finding the correct settings. TBH it sounded pretty good even though it's obviously a compressed format. I think I'll enjoy my ignorance for now until I can get a proper output and decoder setup for uncompressed audio. I've been eyeing
this for a while now, I guess this just made up my mind.
BTW do you know what the format is for compressed? Do they just cut back the bit depth?