Does anyone know what file controls the "auto start" feature of the iPod player in iPhone?

When for example, you connect to a car stereo via bluetooth, the iPod starts up automatically, even if you want to start something else.

Ideally I'd like to start PocketTunes instead, so maybe the auto-start could be reassigned, but just disabling iPod from cutting in whenever it feels like it would be a start (it would stop it taking over after a phone call too, which can be really annoying)

Any ideas?