FWIW, You can just remove the alarm box, or just unplug it, it's in the top of the left hand front wheel well (on a 9-5 anyway) held on with two bolts. The locks will work correctly, and the keyless entry will work too. The downside is that every time you start the car the display will tell you to service the alarm system.
Mine is sitting in my workshop waiting for a roundtoit and battery replacement.