How to update EKPO LABNR & EKES XBLNR thorugh 855 ORDRSP / ORDERS05

Hi ,

We are going to use PO ackwnowledgement through Message Type ORDRSP  and Basic Type ORDERS05. We tested and working fine. Mean time we want to update the Reference field XBLNR as well as Order Ack field LABNR  in confirmation tab.  Let me know the segment and field which i need to pass so that it will  update the values.

Thanks and Regards

Palani