I did a little more assessment on my newly acquired 1991 K100RS (purchased last week) and found the post for the seat hinge has been snapped off from the frame. I'm thinking the only solution is to have a welder install a new post. Wondering if anyone has gone through this before? If they have, any pointers to share?

PHOTO HERE:

It's just a bit of bent mild steel. I'm in the house ATM but if IIRC it's 5mm (or possibly 6mm ) diameter. Either way, it shouldn't give a competent amateur welder any trouble.