How do I fix my leaking Reich Trend E tap?

The tap started to leak at the base after frost damage this winter. I bought a new Reich ceramic cartridge and fitted it, but water still comes out from the base of the tap. I may be missing an 'O' ring (or two) - any idea where I can get details of what I need? The Reich website (http://snipurl.com/1z4vlq) shows a drawing with dimensions, but no details.