switching out of MULTI CH IN 7.1

[1lakerfan]

I cant get my reciever to go to Pllx music (or cinema). When I pust the music or cinema on my remote nothing happens. The part of the manuel to my Denon 2807 that I was reading basically says to push the surround parameter button and on the SB select cenima or music,ect, But when Im in MULTI CH IN 7.1 the surround back option dosnt show up. When I am not playing the a game it will still show MULTI CH IN 7.1 but plays in 2 ch. Can you please help me? I want to put my reciever on DTS Neo 6 music to play the music so sound is coming from all the speakers, instead of playing music in 2 channels. When I am in using opticle and am on dolby digital I would have no problem switching it to DTS cinema or pllx movie. When Im scrolling through the XMB my reciever will say MULTI CH IN 7.1 but will only play in 2 ch. I do understand that the music is not supposed to play in 5.1 or 7.1 unless it supports that format, so thats why I want to switch to DTS Neo 6 music or Dolby Pllx music.