WebMethods Pipeline problem


I am working on webMethods IS & ES integration. In Devlopment environment when an order published from ES to IS, I did not see any problems in the structure(IS doesnot dropping any fields that doesnot contain any value). We moved this code to “Test Environment”, I got some problem in the structure, if any field doesnot contain any value “webemthods IS” is dropping that field from the structure. Could any body explain this, why in different envionments behaves differently.