I'd have though you could get a local engineering firm to helicoil it for you.
shouldn't cost too much, probably around £20.00
Although I have a m/cyl from the early model (916 era) without reservoir or lever you can have for £20 inc posting. You could swap over lever and reservoir from yours then.
Or a cheapy upgrade
http://cgi.ebay.co.uk/ws/eBayISAPI.d...6547 109&rd=1