Insercion de interlocutor con BAPI_SALESORDER_CHANGE

[fitog4]

Hola,

Necesito insertar un interlocutor en un pedido a traves de la bapi BAPI_SALESORDER_CHANGE.
El problema es que me dice que el pedido no se ha actualizado.

    headerx-updateflag = 'U'.

    w_vbeln = mi_pedido.


CLEAR t_partners.
    t_partners-partn_role = 'ZT'.
    t_partnersx-partn_role = 'ZT'.
    t_partnersx-updateflag = 'U'.
    t_partnersx-document = mi_pedido.
    CONCATENATE 'A' centro_transporte INTO t_partners-partn_numb.
    APPEND t_partners.
    APPEND t_partnersx.


 CALL FUNCTION 'BAPI_SALESORDER_CHANGE'
    EXPORTING
*      logic_switch     = logic_switch
      salesdocument    = w_vbeln
      order_header_in  = header
      order_header_inx = headerx
    TABLES
      return           = return
*      order_item_in    = order_items_in
*      order_item_inx   = order_items_inx
*      schedule_lines   = order_schedules_in
*      schedule_linesx  = order_schedules_inx
      partners          = t_partners
      PARTNERCHANGES    = t_partnersx
*      sales_conditions_in     = order_conditions_in
*      sales_conditions_inx    = order_conditions_inx.
      .
      
CALL FUNCTION 'BAPI_TRANSACTION_COMMIT'
*   EXPORTING
*     WAIT          =
*   IMPORTING
*     RETURN        =
            .

¿Que es lo que me falta?

Un saludo y gracias.