Issue with Withholding tax in bapi_acc_document_post

Hi Experts,

We are trying to post an accounting docment with the help of BAPI bapi_acc_document_post. It is posting good except for the
fact that with holding tax is not coming or is coming wrongly. The tax code is taken from BSEG table field QSSKZ.

Code snippet

  IF LS_FINAL-QSSKZ IS NOT INITIAL.
      LS_ACCWITHTAX-ITEMNO_ACC = LS_FINAL-BUZEI.
      LS_ACCWITHTAX-WT_CODE    = LS_FINAL-QSSKZ.
      APPEND LS_ACCWITHTAX TO LT_ACCWITHTAX.
   CLEAR: LS_ACCWITHTAX.