I hope this helps....
There are three locations for relays and fuses: The one that looks to hold the Alarm System Siren ECU is in the passendger compartment, to the left of the steering wheel. Look below the headlight switch. There is a leather panel there that goes from the left edge of the dash to the steering column.
There are two screws on the bottom edge of that panel. Remove those secrews and push the panel downward. The entire panel should come off.
you should see 4 relays on a block. Three are smaller( one positioned vertically, two are horizontal) with a 4th larger relay to the right.
Directly above those relays are 25 fuses, arranged in a 5 X 5 block.
Fuse # F39 will be the second row, first column. It will be red and 10A.
The manual says that fuse controls: Inside roof node, multimedia stystem, AC and heating system node, OBDII diagnostics socket, Alarm System Siren ECU and Motion sensing alarm Ecu.
I can only say try removing that fuse to see if it stops the alarm. I am only looking in the manual and not a mechanic, so this is what its worth. Obviously there are other things that will not work with that fused removed.
This assumes of course that it is the OEM alarm system and not an aftermarket alarm...
good luck. let us know.