Sound attach

hi all, i have attach a sound on a frame in this way:

 
var song_sound1:Sound = new Sound();
this.song_sound1.attachSound("trak_music1");
this.song_sound1.start();

so, i try the movie on preview and all work fine, but if i publish the movie, than i load it inside other movie clip, the sound isn’t reproduced.
How can be possible, and what can i do to solve it?