Don't know about the alarm...but I think all 7**/9** seats can be lifted without a key so I wouldn't bother about getting the lock sorted out, its nonsense anyway!
I never use the key for my seat lock...its quicker the 'other' way.
Its monted on the plastic under tray, its tiny but looks well installed wiring wise, but the siren part could be filled with foam or something then the bike is carried off.
Your alarm should have a micro switch to cover the area where it's mounted. In your case when the seat is lifted it should go off. In weeksys case for example the fairing panel should be protected. This is a requirement of the Thatcham installation certificate.
Would it make any difference if the alarm went off, nobody takes any notice of them. The organised light fingered b&£$%*ds are usually so quick that you dont get much chance to do anything about it?
Lee let me know how you get on as the datatool alarm on my 996 is fitted under the seat. I've never seen any micro switch, but the alarm does go off if you as much as sneeze near the bike.
BTW its a good idea to cover the alarm in cling film, they seem prone to water damage when locaed under the seat.
Nigel, depending upon the model of alarm you can decrease the sensitivity a little by unscrewing the mounting screws a little. The unit shouldn't be screwed down tight anyhow. It won't fall off as it should be mounted into well nuts. It should feel secure but not really tight.