Internal Flash function to load a new MP3

[mwpwalshe]

I am having trouble writing a function to load and play a new mp3 file in flash and I cant find any examples....Any code or links to code would be appreciated - wasted too much time on this already
Thanks

[mwpwalshe]

function updateSong() {
var fo = new SWFObject("flash/previewplayer.swf", "mp3player", "300", "350", "8.0.15", "#ffffff", true);
// need this next line for local testing, it's optional if your swf is on the same domain as your html page
fo.addParam("allowScriptAccess", "always");
fo.addVariable("file","flash/test.mp3");
fo.write("flashcontent");
}
I have this function and it working to update, but it creates a new object everytime which is not what I want, I can get my original object via:
var flashMp3Player;
function init() {
if (document.getElementById) {
flashMp3Player = document.getElementById("mp3player");
}
}
surly I can just update this object:
flashMp3Player. "load new song" ????????

Any Ideas