Similar situation
I'm running an hdmi from my pioneer VSX-1120K receiver to my panasonic (TC-P60S30) 60" plasma. As both are ARC ready, and TV speakers blow, I've been playing the audio from the amazon prime video app on the TV through the pioneer system. However, when I try to do the same thing with the pandora app nothing happens, unless I switch the TV settings to play audio through the TV speakers (which is worthless when theres are party going on).
I've emailed tech support and will post any solution they give, but in the meantime has anyone found a way around this?
Cheers,
Mike