How to find the Table name for field SUMBB from Q0008.

hI .i am calculating special allowance for which i need to fetch the screen field for 'all wages type i .e q0008-sumbb' ..

i have search many thread . finally i get this fm .

m not gettting screen field value.

please guide.

here is the code..\in PAI i have use this fm..

used many table like t510 , t539a , t539a , 

m using fm : CALL FUNCTION 'DYNP_VALUES_READ'

data: v_prog like D020S-PROG,    "" hv also try this frm se37

          v_scrno like D020S-DNUM.

     DATA : l_cprog TYPE sy-cprog,

            l_dynnr TYPE sy-dynnr.

              l_cprog  =   sy-cprog.

              l_dynnr  =   sy-dynnr.

     DATA: LIT_SCREEN_VALUES TYPE STANDARD TABLE OF  DYNPREAD, ,

            LWA_SCREEN_VALUE TYPE    DYNPREAD."LIT_SCREEN_VALUES.     hv  also try      "LIKE  LINE OF LIT_SCREEN_VALUES.

    CLEAR : LIT_SCREEN_VALUES ,

              LWA_SCREEN_VALUE .

     LWA_SCREEN_VALUE-FIELDNAME = 'Q0008-SUMBB'.               "Field to be read

     APPEND LWA_SCREEN_VALUE TO LIT_SCREEN_VALUES.              " Fill the table

     CALL FUNCTION 'DYNP_VALUES_READ'

       EXPORTING

         DYNAME                               =  l_cprog       "v_prog              "'2040'         "v_prog       " l_cprog

         DYNUMB                               =  l_dynnr           "'MP000800'      "l_dynnr

        TRANSLATE_TO_UPPER                   = 'X'

*       REQUEST                              = ' '

*       PERFORM_CONVERSION_EXITS             = ' '

*       PERFORM_INPUT_CONVERSION             = ' '

*       DETERMINE_LOOP_INDEX                 = ' '

*       START_SEARCH_IN_CURRENT_SCREEN       = ' '

*       START_SEARCH_IN_MAIN_SCREEN          = ' '

*       START_SEARCH_IN_STACKED_SCREEN       = ' '

*       START_SEARCH_ON_SCR_STACKPOS         = ' '

*       SEARCH_OWN_SUBSCREENS_FIRST          = ' '

*       SEARCHPATH_OF_SUBSCREEN_AREAS        = ' '

       TABLES

         DYNPFIELDS                           = LIT_SCREEN_VALUES

      EXCEPTIONS

        INVALID_ABAPWORKAREA                 = 1

        INVALID_DYNPROFIELD                  = 2

        INVALID_DYNPRONAME                   = 3

        INVALID_DYNPRONUMMER                 = 4

        INVALID_REQUEST                      = 5

        NO_FIELDDESCRIPTION                  = 6

        INVALID_PARAMETER                    = 7

        UNDEFIND_ERROR                       = 8

        DOUBLE_CONVERSION                    = 9

        STEPL_NOT_FOUND                      = 10

        OTHERS                               = 11

               .

     IF SY-SUBRC <> 0.

* Implement suitable error handling here

     ENDIF.

READ TABLE LIT_SCREEN_VALUES INDEX 1 INTO LWA_SCREEN_VALUE.