You know, I recently did a saturn that the wiring diagram also said it only disarmed with the remotes. But, I found that not to be true. I rolled down the window on the drivers side and I set the alarm. I waited until the alarm set(about 1 minute), then I reached in the window and used the interior handle to open the door. when the alarm started sounding, I placed the key in the ignition and turned it to the run position(I did not attempt to start the car,just turned the key.) The alarm stopped sounding, so I knew if I duplicated what I had just done with the key, I could turn off the alarm with the remote starter.
If that works for this car also, this is what needs to be powered when unlocking - Ignition, keysense and passlock bypass.
So, since the keysense and passlock will already be wired to your ignition 3 output or status output(diode isolated from each other of coarse) I took the disarm wire off the remote starter and split in 2 using diodes(to isolate) and tapped 1 into the the ignition 3 output or status output wire before the 2 diodes on that wire, and the other I went to a relay to power up the ignition wire.
This will power up the ignition, keysense, and ignition wire when unlocking(for about a second), as well as automaticaly when remote starting, as a result disarming the system
If you don't understand or have any questions, just ask, I'll try to answer as fast as I can. But before you ask see if turning the ignition with the key turns off the alarm, post those results and I'll help you with the rest of the wiring to disarm if needed.