Hi, I have changed the head unit in my 307sw for one which plays MP3s, and all works fine, except for it doesn't turn off with the ignition. I can get out of the car, lock it and walk away with the stereo playing, then, after about 3 minutes, it powers down. The standard stereo simply turned off when the ignition was off. It is not a major problem as it is a face off unit, so it encourages me to remove the face when i leave the car, i just wondered if there was a reason for this. I am aware that the standard stereo 'multiplexed', does this affect the ignition switch though?