If you have ABAP knowledge and like to debug, it is relatively simple to debug through an OBN resolve sequence. All OBN calls for both NWBC for Desktop and NWBC for HTML are resolved on the server in one method CL_NWBC_RUNTIME->RESOLVE_NAVIGATION. Just set a HTTP breakpoint for the correct user and client in this method. (Important: NWBC for Desktop will cache resolved OBN calls, first flush the NWBC cache by using a control-click on the Help menu.) The resolving steps involve first retrieving all possible OBN targets that are mapped into the assigned roles, selecting the correct OBN target and finally doing the parameter mapping of incoming parameters onto the target application parameters.