Tom, Here is what I see you need to do.
1. The camera needs power to operate and it will get its power from the Transmission Switch when you put your car in reverse.
2. The Mirror also needs power to operate hand gets it power from the separate + & - wires in your diagram.
3. Now you need to tell the mirror to tun on, so you need to connect the triggers wires together at each point so the mirro know to turn on. See my diagram with the blue lines. I am assuming the trigger wires send ground to the mirror to activate it. The red wires I think are connected to the ground of the cable for the camera.
You can PM me if you need some more help.
