Recommended Panasonic DMP-BD65 setting for Optimal Sound

[WalleO]

I have an onkyo SR 706 AV receiver and just recently bought a DB 65 as a blu-ray replacement for my PS3. I am interested in getting the best possible sound for my system as i'm already pleased with the visuals. The issue i'm having is I can only get the HD-DTS to light up on my AV when i choose bitstream in my sound options, when i choose PCM, my reciever reads " Muiti..." but all 7 of my speakers output sound. when i choose bitstream in my player sound options, i get sound on all my 5 speakers but no sound on the two rear ones. I DO get the HD DTS MSTR light up on my receiver. Im i doing something wrong?