I think 2.0 Mono might just be the same signal output from both channels but no seperation? For example, If someone is talking on the right side of the screen the voice is still output at the same level from both channels. Get me? As for playing Mono in Surround Sound. The reciever only knows what type of signal it is through a optical or coaxial cable right? What if instead of using the digital cable, use the analog cables while watching this movie instead. Then try a dsp mode, see if that will work!
-Joel-