Let's read the manual as the specs do show HDMI input (not to be confused with HDMI ARC!!!)
Page 8 writes: "Audio decoder
- Supports WMA 10 Pro (Up to 5.1)
- Does not support WMA lossless audio.
- Supported ADPCM IMA, MS.
- Does not support ADPCM (A-Law, μ-Low)
- Does not support QCELP, AMR NB/WB
- Supports vorbis (Up to 2ch),
- Supports Dolby Digital Plus (Up to 7.1ch)"
There's much more later but you can't output DD TrueHD or DD+ via the optical cable.
REMEMBER I won't write at length things that are on the web. This means for 7.1 you would have some 7.1 source in DD+ input to this on HDMI. Optical has been written up why it doesn't work for some time.