For that you have to use the analogs outs on the player or via HDMI.
It could be a setting on the PS3.
It should be working.
I have a onkyo 605/kef 3005 setup. I was watching my hd cable today and I noticed on the receiver it says dolby d while watching the football game. Sure enough there is the main audio out of the front 3, with the surrounds putting ambient crowd noise out. Nice.
When I put in the Rocky Balboa blu-ray via my ps3 connected thru the reciever via hdmi, i get "all ch st" on my reciever despite selecting the 5.1 pcm uncompressed track. When listening to the fight sequences, it's not 5.1. The surrounds put out the same stuff as the fronts.
The answer is probably pretty obvious, but I'm having a hard time with this. Any help would be appreciated. Thanks.