I just did the same thing last week, it was fairly simple to de-solder the main power connection from the PCB. The taps are labeled clearly on the back side of the board. You can wire the power to a common source, but be sure that you connect the dome light ground to the dome light ground for your vehicle and the DVD ground to a constant grounding source. AV out taps are labeled clearly on the board as well.
Dan, January 2008