Hi MPB,
I'm in the same situation. I have corrosion on the connector, so I cut it off, and probed the 6 wires with my multimeter. I have the same coloring scheme as you, and each color maps to the same pin. I used a punch down tool to add a new RJ45 keystone jack, but my camera is still not working. For the 4+5 and 7+8 pins that are connected, did you short them together with a jumper in your RJ45 jack, or did you just connect one of those pins?
thanks.