Not to be biased.
But BMW sells Convertible top cleaner for like $5 or is it $7.
Works perfectly. I've cleaned Z4s and 330CiCs.
Although, I do have to say.....that looks like an awesome job PhotoGuy!

I wonder how dirty it was before you washed it.
I'd like to see a before and after shot, whenever you get around to doing it next.
How much was it?