My first question would be in what format does the OEM camera send the data, and is the new camera compatible? If it's something like a standard composite signal then it should be doable.
In your diagram, the FUSE (GN-VT, pin 1) should be your positive power (12V) and the GROUND (BK-BU, pin 5) your ground. I would check with a multimeter before hooking up anything to these.
The naming on the others is a little confusing. Looking at the diagram and not the connector, the Red and Black wires run to the APIM, carrying your video signal (plus a shield). I don't know what the White wire running to the BCM is for, unless it causes the signal to be mirrored (flipped horizontally), but this is a complete guess.
Hopefully this gets you started, and someone else will chime in with better info.