To request System- or Application-Acknowledgements, you have to request them before calling the Outbound Proxy in your ABAP Program:
DATA: l_proxy TYPE REF TO z…,
acknowledgment_request_details TYPE PRX_ACK_REQUEST_DETAILS,
async_messaging TYPE REF TO if_wsprotocol_async_messaging.
CREATE OBJECT l_proxy.
async_messaging ?= l_proxy->get_protocol( if_wsprotocol=>async_messaging ).
acknowledgment_request_details-application_ok = abap_true.
acknowledgment_request_details-application_error = abap_true.
acknowledgment_request_details-system_ok = abap_true.
acknowledgment_request_details-system_error = abap_true.
async_messaging->set_acknowledgment_requested( details = acknowledgment_request_details ).
