Surround Sound 7.1 not working with Blu-Ray player

[bmbocskor]

I have a Samnsung 52" 1080 LCD, a Samsung BD-P-1500 Blu-Ray Player, and a Onkyo TX-SR606 7.1 Surround sound receiver. Then I have an HDMI input from the cable box to the receiver, and an HDMI input from the Blu-Ray player to the receiver, and an HDMI output from the receiver to the TV. I get 7.1 surround sound on cable, but never on the Blu-Ray player. The Blu-Ray movies say 5.1 Dolby Digital. I used to have a 5.1 receiver, and all 7 speakers worked, but not on 7.1. Any suggestions on how I can get this working?