It's a good question. Let us know how it goes. I've never sold any membership site. Just email them and let us know.
I'm interested too to know how, I've seen a product that claims to be able to do it and alot more features called JVmanager http://www.jvmanager.com but I feel it's WAY TOO EXPENSIVE, I Don't know, if anyone here is a clickbank vendor that is using a recurring payment site OR is an affiliate for a recurring payment site we'll be glade if you let us know how you done it. warchief