Рисуете на кнопке поле ручками и обращаетесь потом
Код:
private function changeLabel(sim:SimpleButton,_str:String):void{
((sim.upState as DisplayObjectContainer).getChildAt(1) as TextField).text = _str;
((sim.downState as DisplayObjectContainer).getChildAt(1) as TextField).text = _str;
((sim.overState as DisplayObjectContainer).getChildAt(1) as TextField).text = _str;
}
Исходничек
http://www.murmadillo.tut.su/html/me...utton-href.zip