Door trigger and Dome Light wire

Im gonna install a Crimestopper CS2004TW1 alarm into my 96 accord.  I've researched quite a bit on this site, btw this is the most helpful resource Ive found, but Im still a bit confused about one thing.  On my car, the door trigger and dome light wire is the same wire (negative trigger).  I was just going to wire the door trigger and dome light wires off the alarm to this one wire, but then I got to thinking.

Could I hook the dome light wire off the alarm straight to the dome light wire on the car, then take a diode, hook the cathode side to the dome light wire on the car, and the anode side to the door trigger wire on the alarm?  BTW these are all negative triggers (I believe its opposite with positive voltage).  I experimented earlier with the function of the dome light wire on the car, and it doesnt affect the key chime or the door open illustration in the gauge cluster, so I think this idea will work.  Just want to make sure before I dive into the car tho.  Thanks!

U should be able to hook up both the Dome Lite wire & the Door Trigger wire from the Alarm to the vehicle Dome lite wire.  Be sure & check to see if your Alarm requires a Relay for the Dome lite function.

* Door Trigger In Pin #5