My shutter release button exploded.

My shutter release button exploded on my out of warranty camera. I was just depressing it while taking a photo. It seems that this is a common problem with these shutters, and I've noticed that they changed the shutter from these round versions to the slim narrow ones in the W120. Anyways, the button and the spring has come out. The button has a narrow pin that connects to the center, and this broke off. The end of the end of the pin that came off the button is still stuck there and I can put the button on and make the camera work, but it doesn't stay on. I've noticed ebay sellers that sell the button and spring for only $4. How would I remove the end of this pin and put a new button on?

Fixed. Used the level 2 service manual (free download) to dissemble the camera. Really bad design. Had to remove side, front, back plates, then LCD, then back electronics PCB and then remove the top block. Initially I got a $4 shutter button and spring from ebay, but it is impossible to attach to the broken block. It's one unit. Ordered the entire top block on ebay for $10. Then put back everything.