Actionscript 3 :: XML Playlist With Single-Track Looping?

My plan for my website is to have music tracks pulled from an XML file which act as the background music for the various .swfs loaded by the menu buttons. I.e. hit 'Home', and it takes you back to the home .swf and plays the appropriate music. I want to do this through XML rather than attaching the music directly to the .swf to cut down on load time (syncing isn't a concern), as I can't seem to retain audio quality without bulking up the .swf significantly.

I'm encountering two problems: one is that with the current code, the music only plays once, and doesn't loop. The other is that I want the functionality to play one song as an intro, and then continue to loop another. I.e., hit the home button, intro plays, followed by the looping section, and never returns to the intro unless you hit home again. I can't seem to figure out how to manage either of these things short of creating a unique function for every single button.

Here's the code I'm using:

var my_songs:XMLList;
var my_total:Number;
var my_sound:Sound;
var my_channel:SoundChannel;

[code]...