BADI MRM_WT_SPLIT_UPDATE fail

Question

Hi guys.
I tryed use this BADI but it not work... I saw the notes:
http://service.sap.com/sap/support/notes/1286713
and
http://service.sap.com/sap/support/notes/1156325
but they cant help me too.
My problem is: I need to change the first "tax code" like below:
for that, I insert the code in BADI MRM_WT_SPLIT_UPDATE.
  DATA: ls_rbws TYPE LINE OF mrm_tab_rbws.
te_rbvs[] = i_rbkpv-h_rbvs[].
te_rbws[] = i_rbkpv-h_rbws[].
LOOP AT te_rbws INTO ls_rbws.
ls_rbws-wt_withcd = 'I2'.
MODIFY te_rbws FROM ls_rbws.
EXIT. "change only first item
ENDLOOP.
after pass this BADI, the tax not change.
Please.. anyone can Help me?

Answer 1

I find one solution, it's not the best, but save me.
I put a ENHANCEMENT point in FM FI_WT_READ_LFBW and append the table  x_lfbw with my tax.
if anyone give a better soluction, please, put here
below how i put my code:
IF sy-tcode = 'MIRO' OR
      sy-tcode = 'MR8M' OR
      sy-tcode = 'MIR7'. 
*Get memory fields
ASSIGN: ('(SAPLMR1M)DRSEG-EBELN')    TO <fs_d>,
              ('(SAPLMR1M)DRSEG-EBELN')  TO <fs_i>.
[...put your code...]
LOOP AT t_imposto INTO v_imposto.
           t_lfbw2-lifnr = i_lifnr.
           t_lfbw2-bukrs = i_bukrs.
           t_lfbw2-witht = v_imposto-witht.
           t_lfbw2-wt_subjct = 'X'.
           t_lfbw2-wt_withcd = v_imposto-wt_withcd.
           APPEND x_lfbw2. CLEAR x_lfbw2.
ENDLOOP.
ENDIF