How to copy MIRO header text to account document line item automatically

Question

HI Experts,
I really need your help or advices , my question is as follows, thanks.
After goods receipt , I do invoice verification at t-code MIRO , and it'll produce an account document by system.
at MIRO, I key in the purchasement description on the header text column (INVFO-SGTXT) ,
and after posting , the header text only appear in account document's account payable item ,
it's blank in GR/IR and tax item. 
How to do could let the GR/IR and tax item have the header text too at column BSEG-SGTXT which produced by system?
p.s.
I  have try to use BADI:  AC_DOCUMENT , Method: CHANGE_AFTER_CHECK
and declare  a couple of parameters to check the value,  as follows
DATA: WA_HEADER TYPE ACCHD,
           WA_ITEM TYPE ACC_DOCUMENT-ITEM,
           WA_ITEM_AMOUNTS TYPE ACC_DOCUMENT-ITEM_AMOUNTS.
WA_HEADER = IM_DOCUMENT-HEADER.
WA_ITEM = IM_DOCUMENT-ITEM.
WA_ITEM_AMOUNTS = IM_DOCUMENT-ITEM_AMOUNTS.
but, in the parameters , I don't see any column to access INVFO-SGTXT value.....
Thanks a lot in advanced.
Best Regards,
Yacoa

Answer 1

HI  SAPFICO,
Thanks for your advice,
I  have follow the link , and create an function model named ZSAMPLE_INTERFACE_00001025(copy from SAMPLE_INTERFACE_00001025),
and also run  the  setting  in FIBF....
I write some code in my function , as follows,  but it doesn't work after  I do MIRO
and it's still blank of the account document's line item.
p.s. even make a breakpoint at the function , it doesn't stop and stay at the breakpoint when I execute MIRO, so werid....
FUNCTION ZSAMPLE_INTERFACE_00001025.
""區域介面：
*"  IMPORTING
*"     VALUE(I_BKDF) LIKE  BKDF STRUCTURE  BKDF OPTIONAL
*"  TABLES
*"      T_AUSZ1 STRUCTURE  AUSZ1 OPTIONAL
*"      T_AUSZ2 STRUCTURE  AUSZ2 OPTIONAL
*"      T_AUSZ3 STRUCTURE  AUSZ_CLR OPTIONAL
*"      T_BKP1 STRUCTURE  BKP1
*"      T_BKPF STRUCTURE  BKPF
*"      T_BSEC STRUCTURE  BSEC
*"      T_BSED STRUCTURE  BSED
*"      T_BSEG STRUCTURE  BSEG
*"      T_BSET STRUCTURE  BSET
*"      T_BSEU STRUCTURE  BSEU OPTIONAL
DATA: C_SGTXT TYPE BSEG-SGTXT.
IF SY-TCODE = 'MIRO'.
  READ TABLE T_BSEG INDEX 1.
  C_SGTXT = T_BSEG-SGTXT.
  LOOP AT T_BSEG.
    IF T_BSEG-SGTXT IS INITIAL.
      T_BSEG-SGTXT = C_SGTXT.
      MODIFY T_BSEG.
    ENDIF.
  ENDLOOP.
ENDIF.
ENDFUNCTION.
Edited by: Yacoa Chen on Mar 30, 2011 9:54 AM