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>