Flex Chart Sorting ColumnSeries Order - sorting

Question

I am trying to create a BarChart that will display values within a ColumnSeries in an order dependant of there value.
So for instance, If I had a ColumnSeries in a BarChart , one showing profit, the other showing expenses, it will render correctly if the profit is more than the expenses because the expenses series is rendered on top.
However, if the expenses is more than profit, the profit will not be viewable as it will be rendered underneath expenses.
At this point I am going to try and include an image to display my problem...
OK it turns out that I am not allowed to display an image :(
The image did show that profit in February is 500 but the profit of 300 in January is hidden because the Expenses of 500 is displaying over it.
You can run the code below to create the example:
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script><![CDATA[
import mx.collections.ArrayCollection;
[Bindable]
public var expenses:ArrayCollection = new ArrayCollection([
{Month:"Jan", Profit:300, Expenses:500},
{Month:"Feb", Profit:500, Expenses:300}
]);
]]></mx:Script>
<mx:Panel title="Bar Chart">
<mx:BarChart id="myChart" dataProvider="{expenses}" showDataTips="true" type="overlaid" >
<mx:verticalAxis>
<mx:CategoryAxis dataProvider="{expenses}" categoryField="Month" />
</mx:verticalAxis>
<mx:series>
<mx:BarSeries yField="Month" xField="Profit" displayName="Profit" />
<mx:BarSeries yField="Month" xField="Expenses" displayName="Expenses" />
</mx:series>
</mx:BarChart>
<mx:Legend dataProvider="{myChart}"/>
</mx:Panel>
An obvious solution to this would be to make the BarChart type 'clustered' as both values will be seen, however my client requires the BarChart to be 'overlaid', so currently some smaller values are hidden.
I would expect that there is a way to sort the order of the BarSeries but I cant seem to find how and I would really appreciate someone's superior knowledge on charting. ;)