I had the same issue happen a few years ago. I dropped the plane on a concrete floor. It landed straight on the toe and the stud popped off. It's not an expensive plane (bought mine some time in the 80's), but I really like it. Anyway, took it to a local machine shop to see if they could re-weld the stud. They said they would try and expressed their doubts. When I went to pick it up they had instead added a new stud by drilling/taping the toe plate. This is not a great solution and I don't recommend it. However, after sanding the sole back completely flat the plane works fine. I still use it.
I think my real problem was the guy I took it to didn't really understand planes and the importance of a flat, smooth sole. I'd look for a machinist who could re-weld the stud. Seems it should be doable. You may have to re-flatten the sole when you get it back.