Loop video with actionscript

hi every/anyone

i made a little movie with sound with vegas video editor.
now i want it to loop in flash mx.
it’s a movie with a beat, so it has to be looped very accurate, otherwise at the end of the beat, it holds for a fraction of a sec and then re-begins.
how do i do this???
it’s an avi.

thnx in advance,

grenouille.