To invoke BOSS business object custom actions, it is sufficient to use the Simple HTTP REST Data Source type, configuring the Input Parameters, Request Body Template, and Data Profile manually. To invoke the custom action using the declarative Invoke API page process, workflow activity, or the APEX_EXEC.EXECUTE_REST_SOURCE procedure, configure the Data Profile columns with appropriate selectors to identify which response payload data you want to return to the caller. Then, add OUT parameters to the REST Data Source operation of type Data Profile Column.