add field in Lean sales order in FPM on ehp4

Hi,

I've got a customer where they have a field on additional data B in VA01. We need this field on the lean sales order web dynpro screen. they customer are on Ehp4 at the moment.

I've appended the field to the two structures

TDS_HEAD_COMV

TDS_HEAD_COMC

and added the mapping in LORD_MAPPING.

I managed to get the field on the screen in the configuration. However when i add a value to the field and press enter, the value disappears. If i use the display sales order on an existing order with the value filled out, then the value is passed from the field in VBAK.

Can someone help me on what i am missing to get this working. The enhancement workbench for lean sales order is only from ehp5 :-(