So it's 2012 and I finally got my first universal remote

. As I'm setting it up there's something I want it to do, but since this is my first experience with Harmony I'm not sure if it's even possible:
I set up a "Watch TV" activity that controls my DTV box + Denon AVR, but I want to know if it is possible for me to access the AVR menus easily
without changing devices or activities. I successfully re-mapped two of the color coded buttons to pull up various Denon menus, but after the menus come up I'm not able to navigate them (all directional keys command the DTV box). Can what I want be done and if so, how? If possible I'd like to be able to control both the DTV and AVR within the same "Watch TV" activity, without having to look at the 700 screen to change something.
thanks in advance.