Возникла потребность до проводки документа движения материала выполнить моделирование бух. проводок.
Способ 1Ставим точку останова тут 
SAPMM07M 
 f-beleg_ergaenzen 
CALL FUNCTION 'CKMV_AC_DOCUMENT_CREATE'
Смотрим структуры XACCIT[], XACCCR[]
Способ 2Можно вставить туда свой экран....

Я скопировал SAPMM07M в ZSAPMM07M 
Создал транзакцию Z_MB01, Z_MB04, Z_MBST, Z_MB1B, Z_MB1A
Добавил эти транз в табл T158 , T158B
Вставил свой экран перед CALL FUNCTION 'CKMV_AC_DOCUMENT_CREATE'
MIGO, MB01 и др. при этом работают по-старому.
Работает.
* SAPMM07M 
* f-beleg_ergaenzen 
*  {  ЗЮ  2011-06-08  Моделирование проводки
    DATA z_ucomm     TYPE  sy-ucomm.
    DATA gt_tab     TYPE zzs04114_94 OCCURS 0 WITH HEADER LINE.
    DATA wa_tab     TYPE zzs04114_94.
    DATA wa_xaccit  TYPE accit.
    DATA wa_xacccr  TYPE acccr.
    LOOP AT xaccit INTO wa_xaccit.
      CLEAR wa_tab.
      MOVE-CORRESPONDING wa_xaccit TO wa_tab.
      LOOP AT xacccr INTO wa_xacccr
      WHERE awtyp = wa_xaccit-awtyp
      AND   posnr = wa_xaccit-posnr.
        IF wa_xacccr-curtp = '00'.  " USD
          wa_tab-curtp00   =  wa_xacccr-curtp.
          wa_tab-waers00   =  wa_xacccr-waers.
          wa_tab-wrbtr00   =  wa_xacccr-wrbtr.
          wa_tab-wrbtrc00  =  wa_xacccr-wrbtr.
          CONDENSE  wa_tab-wrbtrc00.
          TRANSLATE wa_tab-wrbtrc00 USING '.,'.
        ENDIF.
        IF wa_xacccr-curtp = '10'.  " RUB
          wa_tab-curtp10   =  wa_xacccr-curtp.
          wa_tab-waers10   =  wa_xacccr-waers.
          wa_tab-wrbtr10   =  wa_xacccr-wrbtr.
          wa_tab-wrbtrc10  =  wa_xacccr-wrbtr.
          CONDENSE  wa_tab-wrbtrc10.
          TRANSLATE wa_tab-wrbtrc10 USING '.,'.
        ENDIF.
      ENDLOOP.
      APPEND wa_tab TO gt_tab.
    ENDLOOP.  " xaccit
    CALL FUNCTION 'ZZFM_MM_ZMIGO_SCR_9001'
      IMPORTING
        z_ucomm = z_ucomm
      TABLES
        gt_tab = gt_tab[].
    IF z_ucomm <> 'Z_OK'.
      SET SCREEN 0.
      LEAVE SCREEN.
    ENDIF.
*  }  ЗЮ  2011-06-08  Моделирование проводки
    CALL FUNCTION 'CKMV_AC_DOCUMENT_CREATE'
      EXPORTING
        i_comp             = component
      TABLES
        t_acchd            = xacchd
        t_accit            = xaccit
        t_acccr            = xacccr
        t_accit_ext        = gt_accit_ext
      CHANGING
        needs_smbew_update = vw.




*----------------------------------------------------------------------*
***INCLUDE LZZGF_MM_ZMIGOO01 .
*----------------------------------------------------------------------*
*&---------------------------------------------------------------------*
*&      Module  STATUS_9001  OUTPUT
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
module STATUS_9001 output.
  SET TITLEBAR  '9001'.
  SET PF-STATUS '9001'.
endmodule.                 " STATUS_9001  OUTPUT
*&---------------------------------------------------------------------*
*&      Module  DISPLAY_OUTTAB  OUTPUT
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
module DISPLAY_OUTTAB output.
*
endmodule.                 " DISPLAY_OUTTAB  OUTPUT
*&---------------------------------------------------------------------*
*&      Module  SET_CURSOR_9001  OUTPUT
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
module SET_CURSOR_9001 output.
  SET CURSOR FIELD 'Z_NO'.
endmodule.                 " SET_CURSOR_9001  OUTPUT
*&---------------------------------------------------------------------*
*&      Module  FCODE_9001  INPUT
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
module FCODE_9001 input.
  CASE ok-code.
    WHEN 'Z_OK'.
      9001_code = ok-code.
      CLEAR ok-code.
      SET SCREEN 0.
      LEAVE SCREEN.
    WHEN 'Z_NO'.
      9001_code = ok-code.
      CLEAR ok-code.
      SET SCREEN 0.
      LEAVE SCREEN.
    WHEN OTHERS.
  ENDCASE.
endmodule.                 " FCODE_9001  INPUT
*&---------------------------------------------------------------------*
*&      Module  EXIT_9001  INPUT
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
module EXIT_9001 input.
  CASE ok-code.
    WHEN 'CANC' OR 'EXIT'.
      CLEAR ok-code.
      SET SCREEN 0.
      LEAVE SCREEN.
  ENDCASE.
*
endmodule.                 " EXIT_9001  INPUT