domnant,

The 5.1 optical in the back of the television is for the tuner only. It will not perform pass-through operation, such as Blu-Ray-via-HDMI through that optical port.

With your receiver's optical in, you could hook up one of the following:

1. The television tuner (digital)
2. Blu-Ray
3. Game Station

So in this application, it's not possible to hook up the Blu-Ray and Game Station into the TV via HDMI and pass through the optical in the television (it will be transferred to 2.0 audio). So the optical port is designed to send the digital tuner's 5.1 when the channels broadcast in 5.1.

I hope this helps.

--HDTech