Dragging this up again. I know many of you have been waiting on pins and needles to see how this turned out.
I FINALLY got this to work!! NO, I haven't been working on it since my last post. Stepped away from it for a while, then recently got the bug to give it another shot. Had a few wrinkles due to the fact that the wiring under my dash is a little different due to the previous owner, and I am using the stock Isuzu Tailgate Release button.
So you don't have to read through everything:
With the key out of the VX (and it's armed), one press of the disarm button unlocks both the driver and passenger door. Two presses of the disarm button triggers the rear door popper.
With the key out of the VX pressing the unlock button on either door will also trigger the rear door popper. In eiter of these scenarios the Tailgate Release button will NOT trigger the rear door popper.
With the key in the VX and turned to run, neither the key fob, nor the door unlock buttons will trigger the rear door popper, but the Tailgate Release button in the dash will.
If you want to give this a shot, it's really pretty easy to do and I'd be happy to walk anyone through it.