SAP Fiori Bank Payment approval app. Help please!!

Hi all.

We have installed this app in our systems but only the frontend and data model. The backend? Created from scratch based on the URIs called from the fronted. A lot of debugging to have now the app completed and working. Of course, I still miss some functionality i'm not able to enable it.

Basically I want to make the binding between frontend and backend with success or error messages. I have tried with several things like:

*Returning entity details (PaymentBatch)

copy_data_to_ref( EXPORTING is_data = ls_header
CHANGING cr_data = er_data ).

* Returning a message

GET_MESSAGE_CONTAINER( )->ADD_MESSAGE(
EXPORTING
IV_MSG_TYPE = 'S'
IV_MSG_ID = '/IWBEP/CM_OCI'
IV_MSG_NUMBER = '010'
IV_MSG_TEXT = LS_MESSAGE-MESSAGE
IV_IS_LEADING_MESSAGE = abap_true
IV_ADD_TO_RESPONSE_HEADER = abap_true ).

Of course, i haven't been able to get the success message in the frontend. After some debugging I have seen that frontend is expecting something like oResults. I have tried to add this in my entity PaymentBatch but the code then is not able to find fields like MessageNumber or MessageType. Attached is a screenshot of this debugging.

Can someone help me to understand what should be returned to the frontend?

Thanks in advance.