Streaming TV Through Oppo UDP-205

I’ve recently acquired a 7-channel Amplifier, and am now attempting to use my  Oppo UDP-205 as a Pre-Amp/Processor.  I have not been unable to get multi-channel (7.1) sound while streaming TV to the Oppo via Optical connection.  I only get sound of the front left and right channels even though the Oppo's Audio Processing is set to 7.1.  The TV is a Sony XBR (X800E series).  Here are the Audio Output settings on the TV:

Speakers – Audio system
Headphone/ Audio out – Audio 0ut (Fixed)
Digital audio out – Auto 2 (Output only compressed audio for multi-channel content without change.)
Dolby Digital Plus output – Dolby Digital

I have tried every possible combination of the TV’s Audio Output settings and the Oppo’s Audio Processing settings with no success.  I’d appreciate any suggestions from those of you out there still using your 203/205 as a Pre/Pro.  Thank you!