Mike,
Cabrio.de make the soft tops for many suppliers, including those in the UK and US. Their quality is excellent.
As Larry said, the job is diy-able noting the excellent caveat about not doing it in the winter in an unheated ski school.
I put about a hundred photos of the job on a photo hosting sites and put the link here. A quick search will produce the link and pictures.
It's not a hard job at all, but 2 pairs of hands will be a real bonus. Good luck.
J