I am having an issue with my audio and my PS3. The setup which I had previously (and it worked) was this:
PS3 audio -> coupler -> Line IN port in my PC sound card -> headphones
However, I've upgraded my headphones from analog to USB, so now my soundcard doesn't detect them as a device (I can use them fine on my PC). So If I try to play on PS3, I can see the sound card detects that LineIN is sending audio, but it's not played back to me.
alternatively you could go through the headache of figuring out which mixer to output to that actually goes to the usb headphones. (basically you have to do the settings for headphones and audio card and then mix and match)