Until you have the fix (tumblers, microswitch, whatever it is), simply disconnect the alarm horn in the engine bay. That won't keep your headlights from flashing if the alarm is tripped, but it will cancel the noise. I did this on my 300E until the lock mechanism was replaced. I also used the passenger-side and trunk-lock trick, which really impressed dates who thought I was just being chivalrous. It was annoying the neighbors to have my car start squawking at 6 in the morning when I went to work.
I don't know where the alarm horn is in your engine bay, but I'm guessing it's separate from the car horn (as it was on my W124).
2003 Dodge Durango SLT
2002 BMW E39 530i Sport
1988 Mercedes 300TE
2003 Chevrolet Suburban