iOS4 Media Control Javascript Events?

Question

I'm not sure if this is exactly what I'm looking for,

but I've noticed the iOS4 media controls (double tap home button and slide left to see them) have some control over the HTML5 Audio elements, but is there any way to do a callback for previous and next songs?

if so does anyone know the way I can tap into these callbacks? :)

Thanks in advance,

-Aaron