I've poked around a bit and not found anything informative other than that it was disabled around the ICS or JB release.
Basically, I have a nice new car, it's got the really neat stereo with U-Connect, and I really want to be able to receive MMS messages on the unit.
I'm currently running stock JB (4.1.2) rooted. I also have Cyanogen loaded, but haven't installed it to boot yet. (Still need to backup and FCR)
Is there any method to enable the ability for MMS messages to transmit over BT?