We have SAP_GWFND 740 SP 05.
The Status would be 201 and not 200. My mistake and sorry for that.
However if you see still the behavior is same.
Behavior which we are seeing is,
When Create operation is implemented through Mapping Operations in SEGW i.e., Through Map to Data Source Option, we are bound to implement a Read as well for the same entity or else at the run-time it dumps.
Framework will look for a Read to perform on successful creation and this will return 201 Status with the data which is recently created. The data displayed is the data fetched as per the Read operation.
If at all you want to allow someone to only Create and never want to allow to read that particular entity then do not use Map to data Source Option.
Model the service using SEGW ( I mean to say define the model ), Generate Run-time Artifacts and manually implement Create_Entity in the DPC_EXT class by inserting the Business Logic.