Which blu-ray player do you have? I ask because I want to look at your connection options.
Your TV is probably converting the HDMI audio stream into two-channel stereo (maybe not, but I've only seen one TV that didn't). You audio issue might be due to the TV's decoder. You will probably be better off connecting the blu-ray player audio directly into your receiver, assuming that's an option. You'd keep the HDMI connection to the TV for the best video, but you would connect the digital coax or optical audio connection from the blu-ray player (if available) to an available input on the 1803 (if you have any left).