I think its only bolted on with 2 little bolts from underneath the cross piece, and its pressed on to the aluminium tube. It was a long time ago when i changed mine, take the torque tube off, undo the 2 bolts then carefully cut the rubber mount off without damaging the ali tube then put a new one on.
Dont know where you can get a new rubber mount from, try finding a second hand one maybe
hope this helps