Yup, I've got the same bar, same configuration, same harness also ST8RRBB...here's how I made it work:
#1. Bought a MPC01 controller. Make sure to get one with the harness to make things easier.
#2. In my case, I tied the grey wire from the lightbar to the gray wire from the MPC01. Same thing with the blue wires. If you're doing a permanent setup, splice the wires together.
#3. The MPC01 has three harnesses that plug into the control head itself...aux, comm, and power/ground harnesses. I didn't use the aux harness. The largest harness has a black wire, a yellow wire, and a red wire, and some others. The others I didn't use.
Black=Ground
Red=Power
Yellow=Backlighting
So I just put the black wire to ground, red and yellow to power. Also put the power/ground from the lightbar to power/ground. Turn it on and it should work. If it doesn't, a possibility is that the program currently in the MPC01 is for a different lightbar. So, if you want to program it, you'll need to download the SC software. Hope this helps! (anyone know which agency this is from?)
Links to my SC Liberty videos:
Part 1 (front)
Part 2 (rear)