I have gather some of the relevant circuits from RAVE and here are some pics of the process.
You would need to make a metallic clip of sorts to attach the cable on pin #6 since it is empty (way to go LR saving all of 0.1 dollars on that)
As we can see, from the +V goes to key switch, then fuse, then instruments all the way down to ground.
The connector on the Disco has the pin 6 enabled, the RRC has it empty
It connects into this PCB style connector:
It even has the bulb (black one between the blue and black):
So I made some sort of clip from a connector I had around and attached a cable to it (labeled for later identification, since I will forget what the hell this is :) :
And before calling it done, I did a quick test, ran the cable to ground point (ZF box), battery connected back, key ignition and "voila!"