What is the correct way to set up permissions for an Enterprise Object in an EPT

I've created an Enterprise Object in my EPT, created some actions and views but I can't get the permissions working.  I've add permissions for read and write: "Dimension -> Enterprise -> Enterprise field" - and the role looks like it has permissions to run the "PLT.InsertOrUpdateAttribute" action - but when I try run a create action I get a permissions error saying the role does not have permissions to run the action.