Calling tcode FF.5 in z program

Hi All,

I have a requirement to pick a file from desktop . convert it in different format and pass it to FF.5 (RFEBKA00).

I have used gui_upload to read and after converting format when I try to pass itab to RFEBKA00, I get a dump

Actual parameter too short when passing parameter in PERFORM.

I am calling program using:

  SUBMIT RFEBKA00 USING SELECTION-SCREEN 1000

    WITH

     SELECTION-TABLE iout

     and return .

Can someone tell me how to call this program correctly?

Thanks