mvl_dtmov is my data attribute which I would like to output in dd/MM/YYYY format. Does anyone know how to define it? 
DEF STREAM st1.
OUTPUT STREAM st1 TO c:\temp\movimentos.csv.
ASSIGN SESSION:DATE-FORMAT = "mdy".
FOR EACH multipos.mp_mvlj  NO-LOCK:
   PUT STREAM st1 UNFORMATTED multipos.mp_mvlj.mvl_dtmov ";" SKIP.
END.
OUTPUT STREAM st1 CLOSE.
				
                        
Why do you set date-format to "mdy" if you want "dmy" ? Use dmy and set year-offset to 0 to force 4 digit year