Loadsound external mp3 and play from middle problem

programming flash
1

I am unable to play the mp3 from the middle

mycode:

  [U]Layer1 first frame[/U] 

   var mySound:Sound = new Sound();
   mySound.loadSound("myFavSong1.mp3",true)
   _root.mySound.start(1500,0);

   [U]Button[/U]
    
    on(click)

{

_root.mySound.stop();
_root.mySound.start(1500,0);

}