File to IDOC 4.6c (ORDERS05.ORDRSP) PI 7.11

Im reading a file through the PI file adapter and writing it to the IDOC adapter into 4.6C.

I have overwritten MESTYP in mapping in the EDIDC40 to (ORDSP) but when the IDOC is received in 4.6 the message type displays as ORDERS not ORDRSP and so the Partner Profile doesnt trigger.

 <ORDERS05>
- <IDOC>
- <EDI_DC40>
  <IDOCTYP>ORDERS05</IDOCTYP> 
  <MESTYP>ORDRSP</MESTYP> 

Any help would be appreciated.