go on the vvoc.com and search my username, i have a massive thread on there that started out as a research on how to do the t/c switch, after a lil input from a few people was put together, i managed to do it .
all it is is a short pulse of a certain wire to earth, the wire needs to be picked up in the passenger foot well, in the kick panel on plug X2, there is pics, and run it to the center of the dash next to the stereo and stick a switch in, genuine switch is about $55-80.