Sansa e280 (e200): Exposing control buttons via dock connector.

[t3hbeowulf]

From the POV of Rockbox, how difficult would it be to expose various buttons specific pins on the dock connector or form some kind of protocol to control the player remotely?

The meat of the question is, how well is the 30-pin connector mapped inside the player and how much of this mapping is exposed to the software?   Can I push/talk to any set of pins with a plug-in to Rockbox? 

Ultimately, I'd like to be able to control the player remotely (as track skip, play/pause from my car)  For the sake of this topic, assume I have details worked out on link between the car and some circuitry that will connect to the Sansa.

Cheers!