I'm all set to install a rear view camera in my '06 TL with Dom's converter and a CCD camera. Here's my question: Dom's unit came with a button (switch). After reading some posts from members who have done the install, I believe this is to switch the camera on full time. Or is it to switch to a 3rd video source such as a DVD player? If it is to turn the rear camera on while driving, I'm assuming the camera needs to be powered by a fulltime power source and not the reverse lights. Can anybody confirm the switch purpose and the power source for the camera if relevant?