Synchronous RFC call not receiving response data form PI/PO middleware

[Kurusetti]

Hi Member's,

 I am able to send the data successfully to PI/PO system through RFC call  & from PI/PO system it is showing it has pushed the response data to ECC successfully . But in calling program I am not receiving any response instead the data which I am passing  through  RFC  (VATPOSTINGS ) is also getting cleared. 

  Request :RFC call from ECC =>  PI/PO => external system  (No issue , everything works as excepted )

  Response : external system => PI/PO => ECC ( Response from PI/PO not received  in calling program )

Not able to figure out for what reason I am not receiving the response, Please let me know if there is any thing I have to handle  additionally. 

[Ulrich_Schmidt]

Can you activate the RFC trace in SM59 for the destination pointing to PI/PO and attach here?