Configuring Acknowledgment Requests

Use
     You use this function to define for a particular sender port and client which acknowledgments are requested from the sender.
Procedure

       1.      In the ABAP Editor (transaction SE38), under Program,  enter IDX_NOALE and choose  Execute.
       2.      Enter a sender port and client.
       3.      Decide whether acknowledgments are to be requested or not for the sender port and client. Choose either Request Acknowledgment or Do Not Request Acknowledgment.
The acknowledgments that can be requested are system error acknowledgments, application acknowledgments, and application error acknowledgments.
       4.      To display all message types that are sent using the selected sender port and client, in the Exception List frame, select Display Entries followed by  Execute.
       5.      If you want to define a different rule for a specific message type, in the Exception List frame, select Insert Message Type or Delete Message Type.
       6.      Select the relevant message type and choose  Execute.

source:http://help.sap.com/saphelp_nw04/helpdata/en/44/932e8896b610bbe10000000a422035/content.htm