flex中如何用图像给按钮做皮肤

 
<?xml version="1.0" encoding="utf-8"?> 

<s:SparkButtonSkin xmlns:fx="http://ns.adobe.com/mxml/2009" 
xmlns:s="library://ns.adobe.com/flex/spark" 
xmlns:fb="http://ns.adobe.com/flashbuilder/2009" 
minWidth="42" minHeight="30" 
alpha.disabled="0.5"> 

<fx:Metadata> 
<![CDATA[ 
/** 
* @copy spark.skins.spark.ApplicationSkin#hostComponent 
*/ 
[HostComponent("spark.components.Button")] 
]]> 
</fx:Metadata> 
<fx:Declarations> 

</fx:Declarations> 

<!-- states --> 
<s:states> 
<s:State name="up" /> 
<s:State name="over" /> 
<s:State name="down" /> 
<s:State name="disabled" /> 
</s:states> 
<s:Rect left="0" right="0" top="0" bottom="0"> 
<s:fill> 
<s:BitmapFill source.up="@Embed('images/1_130927114244_1.png')" smooth="true" fillMode="scale"/> 
</s:fill> 
</s:Rect> 

</s:SparkButtonSkin>