Hi Gerrit,
In fact, Edocman and Membership has the same points, they can work well with Joomla ACL. So you can integrate Membership Pro with Edocman without direct bridge.
For example, if you want user should purchase susbcription plan before they can view Edocman category. You can assign the leave the Access level for the Edocman Category is one Joomla user group (We called A). In Membership Pro, you can setup the a subscription plan and select Joomla group A (It means if user purchase the plan, he (she) will be added into Joomla group A - beside Registered group). And he (she) will able to see and access Edocman category.
You see, we don't need any direct bridge plugin between Edocman and Membership Pro in this case.
Thanks
Dam