I have a 9800 Pro AIW card I've hooked it up to my HDTV through the included component video cables adapter which has an orange connection for a digital coax cable. My picture is fine, but I get no sound through my receiver! yes, the receiver is set to decode dig coax
this is basically how it is set up, exacty as described in the manual
obviously Y, Pb, & Pr are fine, i then have line in connected, then I have a 30' digital coax cable from the orange SPDIF connector to the digital coax in on my receiver. like i said, the settings on the reciever are correct.