Harley Sidecar Parts and Help

Hi. I bought an older Harley Sidecar, probably around 1990 vintage. It has a seat back that has a metal spring clip to fasten the seat to a horizontal bar in the sidecar body. It's broken and I need to find another one. Do you know who might have these?

Also, I'm going to switch the sidecar wheel (cast) and drum brake to a 2010 FLHX cast front wheel with disk brake. Do you know anyone who has done this? I'm thinking of using the stock front 2010 FLHX axle and modifying how it mounts. The stock axle has a tapered mount that helps lock it in place and I'd machine a mating part.

Any help, hints or referrals you can give me would be much appreciated.