var MediaSound="";

function PlaySound(){
    var t = 0;
    t = setTimeout("PlaySoundPause()",100);
}

function PlaySoundPause(){
    var agControl = document.getElementById("SilverlightControl");
    var myMedia = agControl.content.findName("mp3sound");

    myMedia.Position="0:0:0.0";
    myMedia.stop();
    myMedia.play();
}