Set attribute for multipla line items

Hi all,

I am working on a Web Dynpro application, I have created this applicaion for an accounting document so it has header data and multiple line item data. As per the requirement I have to put the following logic:

1. When a user enters a value in the field KBLNR on the line item, all the other fields like cost centerm fund, functional area should populate from a database table based on the value of the KBLNR. to get this I have put the following code:

TYPES: BEGIN OF t_kblp,
          fipos     TYPE kblp-fipos,
          kostl     TYPE kostl,
                  END OF t_kblp.


  DATA lv_kblnr TYPE wd_this->element_t_bseg-kblnr.
  DATA: lt_kblp TYPE STANDARD TABLE OF t_kblp,
        wa_kblp LIKE LINE OF lt_kblp,
        lt_bseg              TYPE STANDARD TABLE OF bseg,
        wa_bseg              TYPE bseg.

  DATA lo_nd_t_bseg TYPE REF TO if_wd_context_node.

  DATA lo_el_t_bseg TYPE REF TO if_wd_context_element.
  DATA: ls_t_bseg TYPE wd_this->element_t_bseg,
        lo_api_controller    TYPE REF TO if_wd_controller,
        lo_message_manager   TYPE REF TO if_wd_message_manager,
        lo_nd_tbseg          TYPE REF TO if_wd_context_node,
         lo_el_tbseg          TYPE REF TO if_wd_context_element,
         lt_el_tbseg          TYPE wdr_context_element_set,
         lv_bseg              TYPE bseg.


*
  lo_nd_t_bseg = wd_context->path_get_node( path = `ZDATA.CHANGING.T_BSEG` ).
  lo_api_controller ?= wd_this->wd_get_api( ).

  CALL METHOD lo_api_controller->get_message_manager
    RECEIVING
      message_manager = lo_message_manager.

  lo_nd_tbseg = wd_context->path_get_node( path = `ZDATA.CHANGING.T_BSEG` ).
  lt_el_tbseg = lo_nd_tbseg->get_elements( ).

  LOOP AT lt_el_tbseg INTO lo_el_tbseg.
    lo_el_tbseg->get_static_attributes(
                           IMPORTING static_attributes = lv_bseg ).

  IF lv_bseg-kblnr NE ' '.

      SELECT fipos
             kostl
             pspnr
             saknr
             geber
             grant_nbr
             gsber
             fkber
             FROM kblp
             INTO CORRESPONDING FIELDS OF wa_kblp
             WHERE belnr = lv_bseg-kblnr.
* navigate from <CONTEXT> to <T_BSEG> via lead selection
        lo_nd_t_bseg = wd_context->path_get_node( path = `ZDATA.CHANGING.T_BSEG` ).


* get element via lead selection
        lo_el_t_bseg = lo_nd_t_bseg->get_element( ).

* set single attribute
        lo_el_t_bseg->set_attribute(
          name =  `KOSTL`
          value = wa_kblp-kostl ).

        lo_el_t_bseg->set_attribute(
          name = 'FIPOS'
          value = wa_kblp-fipos ).

              ENDSELECT.
   CLEAR: lv_bseg, wa_kblp.
  ENDLOOP.

now the problem that I am facing is if a user enter two line items ... my code is only brining in the value for KOSTL and FIPOS for the first line item and doing nothing for the second. I debugged and found that loop is working fine and it's going to the second line item successfully but not settting the values of KOSTL and FIPOS for the second line item.

Can you please help me with what I am doing it wrong here.