Business process object (BPO) or entity methods must be added to the Method Reference Library before they can be referenced in a process definition. The method type defined when adding to the library will dictate where that method will be available for use within a process definition.
Note that removing a method reference from the Method Reference Library will not remove it from any process definitions that reference it. As long as the method is still a valid Cúram application method any process definitions that reference it will remain valid.