Ok ! I've found the script (thanks to dalton :
http://www.ofpec.com/yabbse/index.php?board=8;action=display;threadid=15655). After some tests, I've changed it a little, so here's my solution :
1) In the editor, put in your unit's init field : [] exec "nameofthescript.sqs"
2) Put "nameofthescript.sqs" in your mission folder :
#loop
nameofyourunit switchMove "FXStandDip"
~3
goto "loop"
exit
TOPIC SOLVED !!!!!!!!!