Description of the problem:

As the fine grained auth roles are dynamic, there is no apparent way to create them using the backstage ui rbac role creation page. The backstage ui rbac role creation page just gives a drop down of available static resources for plugins. 

If the expectation is that fine grained auth can't be accomplished through the backstage ui (and only can be done via external files ((ie policy.csv)) or the rbac api), then this should be specified in the documentation.