After reading the thread in that link I can defiantly verify that changing apps is a PITA !! I like to use Pro Band and have purchased most of the backing track packs for it. If I start a track playing and then go to change or adjust the tone settings in Amplifi it drops the connection and the music stops, then it reconnects and plays on and I can then fiddle with the settings.
A real show stopper if you plan on using it live for soloing over the backing tracks in a "Guitar Bar" kind of gig. That's why I got the Amplifi 150 in the first place.
The work around is to run the output of the iPad into a computer audio interface, record the track into a DAW, bounce the wav file out as a MP3, then copy the MP3 back to the iDevice in its own folder. Then open that folder in the Amplifis music library and jam on. Works great but it is VERY time consuming.
Oh, maybe a fix is in the works???