I apologize for the confusion.

The television doesn't act as a decoder for optical signals via HDMI. The only 5.1 signal that will pass from the television's optical input is from the tuner for OTA broadcasts. For surround sound from other devices, the optical should be hooked up directly from the source (game console, Blu-Ray, etc) to the optical in on the HT system. Otherwise, the audio will be sent in stereo.

I hope that provides some insight.