I play a lot of iphone games, and they all allow me to play my own music instead of their game's inbuilt music.
Their game continues to play the sound effects, and if I shut off my ipod music their music fades back in.
It's currently possible to let ipod music continue playing by modifying the MMF generated Xcode by just changing the Audio Session Type as seen here:
Setting the audio session type to: kAudioSessionCategory_AmbientSound
Allows sounds from other applications to continue playing in the background, but unfortunately there is no good way of detecting whether or not there is another application playing audio or not.
So what I'm requesting is an update to the iOS extension with the ability to detect if another application is playing audio in the Background. Using this MMF dev's can disable their own in-game music to allow their users to continue listening to their ipod music in the background.
This is a standard feature in every decent iOS game I've played, so it would be a shame to leave something like this out.