How can the BMW Roadster rag top be removed for rear plastic window replacement?

I'm trying to replace the plastic rear window in the ragtop of a BMW Z3 Roadster. Is there any info on the Web on how to do this? Or a Manual?|||Since you are asking this question, I'm afraid that about half way through you are going to wish you hadn't started. Take it to an upholstery shop. At the least, if it gets screwed up they get to replace it.