Problem when updating Billing Block

Question

Hi All,
Scenario : I have created a debit memo request without a billing block.
                In a Separate Program we need to update the Billing block.
                I am using BAPI_SALESDOCUMENT_CHANGE in the following
                manner :
  wa_order_header-bill_block    = 'Z5'.
  wa_order_header_inx-updateflag  = 'U'.
  wa_order_header_inx-bill_block =  'X'.
  call function 'BAPI_SALESDOCUMENT_CHANGE'
       exporting
            salesdocument    = wf_vbeln
            order_header_in  = wa_order_header
            order_header_inx = wa_order_header_inx
       tables
            return           = tb_return.
The update is failing with the return message as
<b>Field 'FAKSK' cannot be copied, because it is not ready for input.</b>
Any Input as to why its failing ?

Answer 1

Hi everybody...
I got the same problem but I do not think the mentioned FM´s will do the job.
At least I do not see how you should specify the desired billing block.
The only import value is the sales order number.
What I really would like to know is WHY this field is locked for the BAPI.
It´s only locked as long it is initial, as soon as there is a value you can change it by using BAPI_SALESDOCUMENT_CHANGE.
That really doesn´t make any sense to me....