Tree Component setIcon

[bebef]

hi, i have this code, and i want to change the icon for one node, and it doesn't work.I put an image on library, with Linkage - Identifier "imageIcon", and seems that do not work.Did i forgot something ?

var myTree:mx.controls.Tree;
var myAudio:mx.controls.MediaPlayback;
myTree.setSize (200, 100);
myTree.setStyle("color", "0xFF0000");
var myTreeDP:XML = new XML ();
myTreeDP.ignoreWhite = true;
myTreeDP.load ("bebe.xml");
myTreeDP.onLoad = function () {
myTree.dataProvider = this.firstChild;
myTree.setIcon (myTree.getTreeNodeAt(1), "imageIcon");
};
var treeListener:Object = new Object ();
treeListener.change = function (evt:Object) {
myAudio.contentPath = evt.target.selectedNode.attributes.data;
myAudio.play ();
};
myTree.addEventListener ("change", treeListener);