how to fill fieldcatalog using internal table by using (REUSE_ALV_FIELDCATALOG_MERGE)

Hello Experts,

                             Can anyone tell me the solution for  REUSE_ALV_FIELDCATALOG_MERGE i have passed final internal table.

data: begin of typ_final,

         matnr like mara-matnr,

         werks like marc-werks,

          end of typ_final.

data: it_final like standard table of typ_final.

CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'

  EXPORTING

    I_PROGRAM_NAME               = SY-REPID

    I_INTERNAL_TABNAME           = 'IT_FINAL'

    I_STRUCTURE_NAME             = 'WA_FINAL'

    I_CLIENT_NEVER_DISPLAY       = 'X'

    I_INCLNAME                   = SY-REPID

*   I_BYPASSING_BUFFER           =

    I_BUFFER_ACTIVE              = 'X'

   CHANGING

     CT_FIELDCAT                  = IT_FCAT[]

  EXCEPTIONS

    INCONSISTENT_INTERFACE       = 1

    PROGRAM_ERROR                = 2

    OTHERS                       = 3

Thanks,

Vinod.