/iwfnd/maint_serivce - does not open Service Implementation

Hello Experts,

I have working standard PO/PR approval Fiori Apps. I am working on extending them, however, when use T code /iwfnd/maint_service and open Service Implementation, it does not open it for me. It works well for TASKPROCESSING services, but does not open service implementation for any other services.

1) I tried /IWBEP/REG_SERVICE to open Service Implementation. I cannot find GBAPP_POAPPROVAL or GBAPP_PRAPPROVAL services there.

2) RFC destination with System Alias is working correctly. I double checked.

I tried looking for notes, I didn't find anything. I am not sure what is missing.

Gateway is a HUB deployment.

System Components -

2) TASKPROCESSING Services -

3) PO Service -

Appreciate your help!

Thanks,

Rohan