problem in modifying control record

Hi All,

My scenario is Purchase order to Sales order. Once PO is created IDOC will be created and that idoc will be taken as source and i will be modifying the idoc in abap mapping as per requirement.

All the segements are being modified and getting updated in IDOC but when i am trying to change the control record its not getting reflected in the r/3 but when i check in moni before comming to r/3 the xml struture has changed as per my requirement even for control record also but while comming from XI control record is not getting changed.

I would like to change senderpartner and sender partner type in control records.

every configurattion steps has been done correctly.

Would request your experiences if you would have faced any this type of situation in your projects.

Thanks in Advance.