NeX, just realized that it is sooooooo simple... lol
Just need to slice the red and yellow wire, and the 2 ends connects to orange/black and white/black wires on the alarm, because the alarm has internal relays... The orange/black wire is the normally closed side of the unlock signal relay and the white/black wire is the common wire of the unlock relay. So, no need to use an external relay to control the OE central locking. The schematic that you draw its just to use with aftermarket C/L, not OE...
Anyway NeX, thanks alot, without your schematic and explanation i couldnt realize how to do it. (Y)