I may have found your issue. Per page 15 of the owner's manual for the TV regarding the TV's optical out jack:
"When the receiver (home theater) is set to On, you can hear sound output from the TV’s Optical jack. When the TV is displaying a DTV(air) signal, the TV will send out 5.1 channel sound to the Home theater receiver. When the source is a digital component such as a DVD and is connected to the TV via HDMI, only 2 channel sound will be heard from the Home Theater receiver."
Let me look into the blu-ray player. Can you connect the audio directly from it to the receiver? Like an optical or digital coax?