Tcode SICF
On the menu list ‘Define services’ click on Edit –> Debugging –> Activate debugging . Tick URL and specify the URL of your web-service to debug, in case of oData-service it would be similar to /sap/opu/odata/sap/ZPSMM_GR_SRV/$batch, for example.
SAP Note 1417159 – External breakpoints – SYSTEM_CORE_DUMPED
SAP Note 1447922 – Watchpoint w/ condition always stops during procedure entry
SAP Note 870454 – Integrated ITS, debugging IAC