You take out insurance to cover these sort of things, maby you should call up or go down an speak to some one at the rental place. They should be able to tell you what you can and cant do. I know if i were to take apart a guitar i rented from my local shop, any insurance i took aout would be void and they will probibly blame anything broken on me taking it apart.
On a side note, how did you like the trem when it was working. I personaly hate them. My mate managed to pull his clean off his £1000 SA prestige. not a pretty sight.