Hello Adrian. I have on older Denon 2807 and you should not have to do all that. I have my rear speakers set to "surround speakers" and I can listen to Cd's in stereo or 5.1 if I wish. Have you seen this: http://batpigworld.com/
It is Batpig's Denon to English Dictionary and it may help you with your setup. Give it a look and see if it helps.