Hmm, interesting point... I would be plugging this thing directly into a giant Pioneer receiver--never the TV monitor--and certainly HDMI is not itself an impediment to 5.1 audio, but details on supported digital audio formats seem a bit scarce now.

Based on all the images (and limited copy) here, it seems that it may need you to plug it directly into the TV and not a receiver.

I could be mistaken, but the video, images and copy all seem to go to the TV.

Does the docs say that the audio is only stereo? Is that a product limitation or an HDMI limitation?

Nope. I don't see anything about the audio at all.

I just know that for my setup, whenever I plug anything into my HDMI port on my TV, I get stereo audio.

It could be that my TV doesn't handle the audio decoding properly, but I imagine that it isn't exclusive to my Toshiba.

HDMI supports 7.1 surround. I'm not sure what kind of setup you have where you get sound from your TV to your sound system, but you can buy an HDMI splitter for something like $10 that will give you an optical audio signal and a video-only HDMI signal.