561T & GM-SL

Okay, wired up the units last night and everything seemed to work perfect by triggering the RS brain by touching the (-) activation wire twice to the ground.  It started right up.  I didn't hook up the wires to the lock and unlock from the GM-SL for two reasons.  1) I don't know what to plug them into on the RS brain.  2)  I don't think I will need them since I am using the factory remotes.  Unless someone tells me different I think I will leave them unhooked.  I did answer my own question from earlier on how to change the settings by grounding the activation input wires.  I think my last question is on the '04 Silverado Crew Cabs, what wire do I hook up to to get a (-) pulse when the lock button is depressed on the factory remote?  Thanks for all your help, 05gt, and everyone else.