How to modify item quantity in an scheduling agreement

Question

Hi,
I'm trying to modify target quantity (ekpo-ktmng) in an item of a scheduling agreement (you can see it in me33l transaction).
When the users tries to modify, using me33l, the quantity of an item in an scheduling agreement, I need to pick this value (ktmng) and modify it according to some rules.
To catch the value I use EXIT_SAPMM06E_016 user-exit, and when the user modifies a value in the i_ekpo register of the user exit I see the new value that the user introduced. But I need to put a new value and it isn't enough with modifying this structure (i_ekpo).
So I think in a bapi, first of all I've tried with BAPI_PO_CHANGE but I receive the following error:
"Not possible to process a scheduling agreement using this function"
How can I change the target quantity of an item in a scheduling agreement?
thanks in advance

Answer 1

Thanks for your reply, I'm trying with the following piece of code:
DATA: w_ekko TYPE ekko,
      t_ekpo TYPE STANDARD TABLE OF ekpo WITH HEADER LINE,
     t_ekpo2 TYPE STANDARD TABLE OF ekpo WITH HEADER LINE,
START-OF-SELECTION.
  SELECT SINGLE * INTO CORRESPONDING FIELDS OF w_ekko
  FROM ekko
  WHERE ebeln = '5500000001'.
  SELECT * INTO TABLE t_ekpo
  FROM ekpo
  WHERE ebeln = '5500000001'.
  t_ekpo2[] = t_ekpo[].
  READ TABLE t_ekpo2 INDEX 1.
  t_ekpo2-ktmng = '69'.
  MODIFY t_ekpo2 INDEX 1.
  CALL FUNCTION 'ME_UPDATE_AGREEMENT_PO'
    EXPORTING
      i_ekko_new       = w_ekko
  I_EKKO_OLD       =
  I_LOGSY          =
    TABLES
  XEKBES           =
      xekpo            = t_ekpo
   YEKPO            = t_ekpo2
  XSVAB            =
But I receive a dump from SAP.
In t_ekpo I put all the items of the scheduling agreement, the I modify one of the (first) and store it in t_ekpo2, but I'm not very sure of this is the good way of working.
Any help would be very appreciated.
Thanks again