Flex实现双轴条状图

1、问题背景

     一般的，柱状图能够实现双轴图，可是怎样实现双轴条状图？

2、实现实例

<?
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" 
			   width="100%" height="100%" 
			   creationComplete="initHandler(event)">
	<s:layout>
		<s:BasicLayout/>
	</s:layout>
	<fx:Script>
		<![CDATA[
			import mx.collections.ArrayCollection;
			import mx.events.FlexEvent;
			
			[Bindable]
			private var chartArray:ArrayCollection = new ArrayCollection([
				{week:"星期一",snake:"5459",cow:"7845"},
				{week:"星期二",snake:"8956",cow:"7845"},
				{week:"星期三",snake:"3562",cow:"7845"},
				{week:"星期四",snake:"7856",cow:"7845"},
				{week:"星期五",snake:"1245",cow:"7845"},
				{week:"星期六",snake:"9656",cow:"7845"},
				{week:"星期日",snake:"6784",cow:"7845"}
			]);

			protected function initHandler(event:FlexEvent):void
			{
				cate.ticksBetweenLabels = false;
			}

		]]>
	</fx:Script>
	<fx:Declarations>
		<!-- 将非可视元素（比如服务、值对象）放在此处 -->
	</fx:Declarations>
	
	<mx:VBox width="100%" height="100%" horizontalAlign="center" paddingBottom="10" paddingLeft="10" paddingRight="20"
			 paddingTop="10">
		<mx:BarChart id="barchart" width="100%" height="90%" showDataTips="true" dataProvider="{chartArray}">
			<mx:verticalAxis>
				<mx:CategoryAxis id="cate" categoryField="week" displayName="星期" />
			</mx:verticalAxis>
			
			<mx:series>
				<mx:BarSeries displayName="蛇数量" xField="snake" yField="week"/>
			</mx:series>
			
			<mx:secondVerticalAxis>
				<mx:CategoryAxis categoryField="week" displayName="星期"/>
			</mx:secondVerticalAxis>
			
			<mx:secondSeries>
				<mx:LineSeries displayName="牛" xField="cow" yField="week"/>
			</mx:secondSeries>
			
		</mx:BarChart>
		<mx:Legend dataProvider="{barchart}"/>
	</mx:VBox>
	
</s:Application>

3、实现结果