Sounds like you need another 'activity' setup so you can have the 990 turned on in 7.1 for audio listening, and a second activity that turns the 990 on for DVD viewing.
When I press the 'watch TV' activity, the 880 turns the 990 on to 'Sat'. When I press 'watch a DVD' I have the 990 default to 7.1. When I press 'watch a movie' the 990 defaults to DVD player in 5.1 surround (or dts, or DD, or, etc).
Does this make sense?
Lonster