I read about your predicament. The Heuer people and the parts houses in Switzerland are under certain restriction of selling parts. Therefore parts are hard to find.
Give this company a try : www.ernst-westphal.de or info@ernst-westphal.de . They maintain a large stock of watch parts, all sorts of brands, but also have access to a world wide data base. Maybe they can find what you need. Their service is very good. I have ordered from them and they do a good job. Let me know if this works.
Good luck. Heinz.