Hi Jef
I am sorry but we don't have plan to add support for webmoney into Membership Pro at the moment. As I can see, it is not a popular payment gateway (I haven't seen many customers request for it).
So in this case, if you want to use webmoney with Membership Pro, I am afraid of you will need to hire a developer to develop it for you.
Sorry if this is an unexpected answer. I am working hard on Membership Pro to improve it, however, I will have to focus on the features which most customers need it first
Tuan
