keydown- keycode help

["RafNeron" <webforumsuser@xxxxxxxxxxxxxx>]

Hi, I want to use th "on keydown" function to, for example, pause a movie or go 
back to the main menu. The problem is I can't find working keycodes except 
RETURN. Using RETURN works in this script:

 on keyDown
   if (_key.key = RETURN) then _movie.go("start")
 end keyDown

  I have try to change RETURN for SPACE or 49 (keycode for the spacebar) and it 
does not work.
 I hope this is clear, doing my best to write in english.
 Anybody could help please?
 Thanks