how did you manage it by accident? Or did you never finnd out? I think I need something that will make the n900 trick the car into thinking there is a call about to come in or something, but which never acgtually happens. Then it should play whatever is on the media payer, like it does for a second before actually dialling or picking up a call. I can't program myself, but maybe someone could teach me how and an app could be written. There must be loads of people with cars that only do calls and having it play music this way would be ace. Perhaps a script that sends whatever the trigger is to a bluetooth headset that says 'get ready for a call' ans just sends that constantly?
I know there is the fm transmitter option, and this will do for now.