Call BAPI_MATPHYSINV_COUNT

Hi I call  BAPI_MATPHYSINV_COUNT fine , but is not work on Materials with serial Number ( Serial Number Is not save and when I try to change Count in Mi05 ,Serial Number list is Empty ) whats my problem ?

how pass value to SERIALNUMBERS ?

         CALL FUNCTION 'BAPI_MATPHYSINV_COUNT'

           EXPORTING

             PHYSINVENTORY = ITB-IBLNR

             FISCALYEAR    = PYEAR

             COUNT_DATE = PDATE

           TABLES

             ITEMS         = I_COUNT

             RETURN        = I_RETURN

             SERIALNUMBERS = I_SN .

        COMMIT WORK .