I went the whole solution. Bought the TV tuner from Chook (about $300) and then bought a Panasonic reverse camera (NTSC) that had a rca plug and now the reverse camera turns on automatically when in reverse, changes from the TV to AV1(with the reverse camera) and when I put it back in D it changes back to TV.
Mind you, you need the park brake overriden (special button from Japan) to be able to view the screen when the park brake is released.
Cheers
Andy