SAP TAX CODE 自动计算税金(BAPI_ACC_DOCUMENT_POST CALCULATE_TAX_FROM_GROSSAMOUNT)

CALL FUNCTION 'CALCULATE_TAX_FROM_GROSSAMOUNT'
  EXPORTING
    i_bukrs   = ''　　"公司代码
    i_mwskz = 'X1'        "税码
    i_waers  = 'CNY'       "币种
    i_wrbtr   = amount   "金额
 TABLES
    T_MWDAT  = t_tax_info.

* Now I loop the t_tax_info table in order to fill the ACCOUNTTAX and CURRENCYAMOUNT tables:LOOP AT t_tax_info.
LOOP AT t_tax_info.
  CLEAR ls_accounttax.
  ls_accounttax-itemno_acc = sy-tabix + .
  ls_accounttax-tax_code = 'X1'.
  ls_ACCOUNTTAX-ACCT_KEY   = t_tax_info-KTOSL.
  ls_ACCOUNTTAX-COND_KEY   = t_tax_info-KSCHL.
  ls_ACCOUNTTAX-TAXJURCODE = t_tax_info-TXJCD.
  ls_ACCOUNTTAX-TAXJURCODE_DEEP  = t_tax_info-TXJCD_DEEP.
  ls_ACCOUNTTAX-TAXJURCODE_LEVEL = t_tax_info-TXJLV.
  APPEND ls_accounttax TO accounttax.

  CLEAR ls_currencyamount.
  ls_currencyamount-itemno_acc = ls_accounttax-itemno_acc.
  ls_currencyamount-currency   = 'CNY'.
  ls_currencyamount-amt_doccur = t_tax_info-wmwst.
  ls_currencyamount-amt_base = t_tax_info-KAWRT.　　"<-----------It's not the base, but gross amount
  APPEND ls_currencyamount TO currencyamount.

ENDLOOP.

U're using CALCULATE_TAX_FROM_GROSSAMOUNT, so the amount transfered to that fm is not the base amount, but it's  the gross amount