I have a setup for this too from my media player. I have to set my WDTV Live SMP to audio out digital via optical and it goes to the Amp. Meanwhile the video is connected via HDMI. This then means no audio is available to the new Panasonic ST50 TV and therefore my headphones. There is also an audiosync problem when setup this way with this TV.
That is why I was after a reco on settings I need to have on the TV to try and get the best digital audio passthrough from the unit, to the TV to the Amplifier.
Thanks for your tip.
The way you have it setup is how I used to do it with my old Samsung plasma which only had one DVI input.