Adicionar componente na tela pelo AS3?

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
                           xmlns:s="library://ns.adobe.com/flex/spark" 
                           xmlns:mx="library://ns.adobe.com/flex/mx" 
                           minWidth="955" minHeight="600"
                           creationComplete="inicio()" >
        <fx:Declarations>
                <!-- Place non-visual elements (e.g., services, value objects) here -->
        </fx:Declarations>
        
        
        <fx:Script>
                <![CDATA[
                        import mx.controls.Alert;
                        import mx.controls.Button;
                        
                        
                        public function inicio():void
                        {
                                var botao:Button = new Button();
                                botao.x = 300;
                                botao.y = 250;
                                this.addChild(botao);
                        }
                        
                ]]>
        </fx:Script>
</s:Application>