Any information on the rear button is near the end of the users manual. I don't have one in front of me, but I believe the other button you are talking about is the ent button. Now both of these have sinigular functions( rear camera on, shuffle background) but I Just discovered the other day that if you use both of these buttons you can enable the dual zone entertainment capability. Say you have an ipod hooked up and a dvd in the head unit. With the rear button on, you can shuffle through background images using the ent button, until the dvd is playing on the screen and the ipod is still playi
