My client uses the wpmu membership module s(not listed but

My client uses the wpmu membership module s(not listed but should be)

My client would like to use PayPal Pro in conjunction with the Membership Module. However it is not an option under Membership...Payment Gateways.

Q: how do we add and offer this option using your plugin?

Screen shot: http://www.bernadettethompson.com/wp-content/uploads/2014/08/ss_wpmu_membership_gateway01.jpg

Please advise