IDoc programming for Requested Delivery Date - Inbound ORDERS

Hi Folks,

I want to manipulate Requested Delivery Date on the Sales Order.

The Field for Req Del Date is RV45A-KETDAT.

But this value is stored in VBAK-VDATU.

When i am trying to modify this value using dxvbak structure, this value is getting populated correctly, but not updating in the table.

Look at the code snippet below.

 if zedidc-sndprn = '0000902000'.
        IF ze1edk03-iddat = '002'.
          MOVE ze1edk03-datum TO zvbak-vdatu.             " Requested Delivery Date
           zvbak-vdatu = sy-datum + 7.
           BREAK-POINT.
           dxvbak = zvbak.
        ENDIF.
        endif.

What's wrong here??

Thanks,

Matt