If you are navigating using AA/GM (displayed on the main screen), can you easily switch back and forth to sirius/radio to switch stations, etc..., or is it an involved process requiring many button pushes, exiting apps, reloading apps, etc...?

I loaded a bunch of MP3 CDs in the stereo this weekend and they work just great. The one thing I don't understand though is how to navigate through the folders - the stereo seems to think all the songs are in the root folder (at least that's what the display seems to say) even though all the...