96 trooper w/ factory alarm

I am adding a keyless entry / remote start kit by VPA (purchased a few years ago through summit) to my 1996 isuzu trooper that has factory alarm(no keyfob or keyless entry).  I want to keep the factory alarm, but I know that I will have to sink the factory alarm (ORANGE / Red (-) ) to ground before the remote start will engage due to the factory alarm's starter kill relay (not to mention the honking horn).  I have an idea on disarming the factory alarm without unlocking the doors (don't want my doors unlocked while car running).  Could i just wire a relay in with the ignition 1, 2, or starter output of the VPA remote start to create a ground for the factory disarm (ORANGE / Red ) ? 

Any comments or ideas?  Is this feasable?

I know i could permanantly disable factory alarm by pulling the fuse or by grounding  the ORANGE / Red wire, but I really want to keep factory alarm.  I don't want to use door unlock to ground it since this would leave car unlocked and running.