Q: Do I have to do any changes to the axis2.xml to make Sandesha2 work?

A: Yes. You have to add a phase named RMPhase to both request flow and the response flow of axis2.xml. In the request flow this should be after the Dispatch phase, and in the reponse flow this has to be before the MessageOut phase. Example phase order:

   <phaseOrder type="inflow">   <phase name="Dispatch" />
   <phase name="RMPhase" />
   </phaseOrder>

   <phaseOrder type="outflow">
   <phase name="RMPhase" />
   <phase name="PolicyDetermination"/>
   <phase name="MessageOut"/>
   </phaseOrder>