Hi Cosmo - only parts vendor I seen a detailed list of softtop frame are Frank Hanel, Germany.
http://www.ar-hanel.de/pdf/spider.pdf
Pages 47-48 shows detailad parts drawing and parts no.
You find prices on his on-line shop
http://www.ar-hanel.de/webshop/index.html
Sorry, all are in German. I use
http://www.freetranslation.com/free/ when I can't translate myself.
Springs shown on drawing at the B-post seem to be pretty standard items, just getting the right lenght. Some nuts and bolts are shown in the drawing but can't see if they are the ones you need.
Good look