2006 4runner alarm sensor

if i wanted to add a dei 504m shock sensor to the factory rs3200 plus alarm system, do i tap into the bcm or the alarm wires?  other mods use the bcm, but wouldnt the alarm wire harness that plugs into factory harness do the same thing?  the alarm add on (just plug and play) monitors the doors, hood, lights, etc, so couldnt taping into the alarm wire harness be just the same as the bcm? id rather do that b/c im using taps and im only messing up wires i could reorder, vs. the bcm.  thanks! 

also, do you happen to have pics or a wire diagram for the wires id be using?

define:

"Make sure that is an actual alarm"-if i added it via harnesses, wouldnt that be easy to find?  the instructions have you tape all modifications with foam ( i guess to prove where changes were made? )  since i cannot add an attachment for the instructions, email me and i can send them to you.

also, "dual zone"-meaning there are 4 wires, ground, power, blue and green.  im assuming one wire is the 1st stage of warning (1 horn honk), and the other wire as the full alarm cycle after the aforementioned wires warning.   what would change?  the guys at g35driver.com use this method, while others use the interior wire harness (bcm?) by the drivers left interior panel.  see the link:

http://g-owners.com/article_read.asp?id=43

http://www.toyota-4runner.org/showthread.php?s=&threadid=20160

hopefully the toyota directions will also help explain my idea.  i already have the dash apart for the oem alarm install, so id rather do it now than taking it apart again.  thanks for all the help.