Pasar de xml a una tabla interna sap

En el siguiente programa podremos transferir un xml a una tabla interna.

El código es el siguiente:

DATA: gcl_xml       TYPE REF TO cl_xml_document.
DATA: gv_subrc      TYPE sy-subrc.
DATA: gv_xml_string TYPE xstring.
DATA: gv_size       TYPE sytabix.
DATA: gt_xml_data   TYPE TABLE OF smum_xmltb.
DATA: gwa_xml_data  TYPE smum_xmltb.
DATA: gt_return     TYPE TABLE OF bapiret2.
DATA: gv_tabix      TYPE sytabix.
DATA: gt_student    TYPE TABLE OF ty_xml.
DATA: gwa_student   TYPE ty_xml.

 CREATE OBJECT gcl_xml.

*Upload XML File
  CALL METHOD gcl_xml->import_from_file
    EXPORTING
      filename = p_p_filout
    RECEIVING
      retcode  = gv_subrc.

  IF gv_subrc = 0.
    CALL METHOD gcl_xml->render_2_xstring
      IMPORTING
        retcode = gv_subrc
        stream  = gv_xml_string
        size    = gv_size.
    IF gv_subrc = 0.
* Convert XML to internal table
      CALL FUNCTION 'SMUM_XML_PARSE'
        EXPORTING
          xml_input = gv_xml_string
        TABLES
          xml_table = gt_xml_data
          return    = gt_return.
    ENDIF.
  ENDIF.


  WRITE:/ 'fecha',6 'moneda',26 'compra', 33 'venta'.
*Convert XML internal table to Target Student table
  LOOP AT gt_xml_data INTO gwa_xml_data WHERE hier EQ 2.
    IF gwa_xml_data-type is INITIAL.

       gv_tabix = sy-tabix + 1.

       READ TABLE gt_xml_data INTO gwa_xml_data INDEX gv_tabix.
       gwa_student-fecha = gwa_xml_data-cvalue.

       gv_tabix = gv_tabix + 1.

       READ TABLE gt_xml_data INTO gwa_xml_data INDEX gv_tabix.
       gwa_student-moneda = gwa_xml_data-cvalue.

       gv_tabix = gv_tabix + 1.

       READ TABLE gt_xml_data INTO gwa_xml_data INDEX gv_tabix.
       gwa_student-tccompra = gwa_xml_data-cvalue.

        gv_tabix = gv_tabix + 1.

       READ TABLE gt_xml_data INTO gwa_xml_data INDEX gv_tabix.
       gwa_student-tcventa = gwa_xml_data-cvalue.

       APPEND gwa_student to gt_student.
    ENDIF.
    CLEAR: gwa_xml_data, gwa_student.
  ENDLOOP.

*Display data
  LOOP AT gt_student INTO gwa_student.
    WRITE:/ gwa_student-fecha,11 gwa_student-moneda,27 gwa_student-tccompra,
            33 gwa_student-tcventa.
    CLEAR: gwa_student.
  ENDLOOP.