I can modify the icons of mx.controls.Tree component using setStyle
tree.setStyle("disclosureOpenIcon",myIcon1);
tree.setStyle("disclosureClosedIcon",myIcon2);
tree.setStyle("folderClosedIcon",myIcon3);
tree.setStyle("folderOpenIcon",myIcon4);
tree.setStyle("defaultLeafIcon",myIcon5);
Where myIconx is of class "Class" which is embedded images. But i need to customize the icons in a way that icons should be drawn using actionscript, we can use a component extended from sprite/uicomponent for showing an actionscript drawing. But how we can use that as a tree icon?