it is possible, after an awful lot of fiddling. when i first got mine the radio used to come on and off everytime you started the engine, then it went into the garage, and came out where you had to turn in on and off manually.
After about 1 hour of going through all the different menus, i managed to sort it. I think you hold down the menu button where you cann alter all the base and treble setting etc, if you hold this down for about 5 seconds, it comes up with more advanced menus (you may have to be stationary for this), if you switch through them you should find somthing.