If TM 1 can`t help you, Giacomo. It is going to cost Close to $300 installed. Kay Ohye has a Video-Perazzi repair that shows you how to do it. Watch it about five times, grow a third hand, and take it apart over a white sheet, so you can find the tiny springs and pins when they go flying. Obviously I speak from experience. One can also remove the old locking block, weld up a new surface and mill it back down to specs. If one has access.....All good
You can just have the locking bolt rebuilt($125) for far less than the cost of a new one with the fitting($200 or more). To replace all of the springs at the same time would cost just the price of the springs.