The new plasma spray weld machines are what Oscar referred to. He had someone that use that to build up a small amount of metal on the hook and then file fitted it. I believe Kirk Merrington has also used the plasma metal spray to apply the additional metal.
Either way it all boils down to file fitting with a smoke lamp.
In talking with Steve Bertram, he described the welding buildup as only at the back of the hook since that is where the wear is. That makes it much much easier than welding up the whole hook which would cause you to loose the location of the hook in the verticle axis.
