Q: How do I add the AccordionTreeMenuV3 on stage in runtime?

A: Here is the script you have to adapt to your project.

var acc:AccordionTreeMenuV3;
//create a listener, to find when the button is pressed
var lis = new Object()
buttonOne.addEventListener("click", lis)
lis.click = function (event:Object)
{
// when the button is pressed, we call de attachMenu function to create another AccordionTreeMenuV3AS3
attachMenu("buttonOneXML.xml")
}
// the function that attach a new AccordionTreeMenuV3AS3.
function attachMenu(xm:String)
{
// if another menu already exist, we remove it.
if(acc != null)
removeMovieClip(acc)

// we create the menu.
acc = this.attachMovie("AccordionTreeMenuV3","acc",this.getNextHighestDepth())
// set the xml for the menu.
acc.xmlPath = xm;

// we set the width of it (initial is 100).
acc.width = 200

//we set a random position, to know that a new menu was created.
acc._x = Math.random(100)*350
}