You have to goto the audio menu on the PS3 & change it to toslink. If you want to use the tv speakers, you have to reverse that... PS3 audio menu change toslink to HDMI.
It is very dumb, that I know, Sony is the only company that makes there players not output audio over more then one output at a time.
I'm having problems getting my surround sound working out of the PS3. I have a Yamaha HTR-5940 receiver and a Samung LN46B750 TV. My receiver is not HMDI compliant so I ran and HDMI cable from the PS3 to the TV and a Digital optical cable from the PS3 to the receiver. I can't seem to get any sound. I've tried to update the PS3 audio settings however it won't allow me to save the change to 5.1. I assume it does not recognize it. Any ideas what I'm doing wrong? Thanks