Loop sound

my problem is apparently very simple: i loaded a sound in the first frame of scene 1 (i have several scenes) using a beahviorof frame, load sound.i did this beacuse i need the sound to be controlled by a mute button, and when doing the behavior for the button it asks me a sound instance name (which only appears when you load a sound with this beahviour), otherwise i would justdrag a sound to the stage. the problem is that i need this sound to be playing continously, i mean a loop. but the sound starts fine, and stops when finishes.how can i make this sound a loop???
of course, i know that i just to modify the sound properties in the property inspector, but i did this with the frame i put the behaviour in and nothing.
any ideas???