I don't know if you care about the chime working if you leave the headlights on or not, but here is how to just disable it from going on if the key is in the ignition w/ the door open:
just take the plastic shrouds off the steering column. You'll see a little black two wire harness that connects to the ignition. Unhook the connector. This will keep the buzzer from going on when the key is in acc or you have the door open, but it will still sound if you have left your lights on or low fuel, etc.
Mike