I recently purchased a express van and noticed the standard alarm system is practically silent, but the passkey3 theft deterrent system does provide some peace of mind. So I wanted to improve it with the added security of a proximity alarm and theoretical benefits of a siren alerting me when it goes off.

Fast-forward through two complete aftermarket alarm installs (Viper 3108V / DS4+) and both don't disarm the factory system. So if I use the aftermarket fobs my hazzards are consistently flashing.

I cant be the only one to encounter this obstacle.. I haven't been able to find any information on what excatly the standard package is or any programing information regarding the stock security features. I see the red led and a button attached to the parking brake release but thats really all I know..
Is this just an expensive exercise in futility or is there some way to link these systems in perfect harmony.. two fobs for the same purpose is ridiculous. I guess the flashing hazards are a useful defensive driving tool, very professional..