[flexcoders] get data from other LineSeries dataprovider in the dataTipRenderer

[arno.manders]

I have a linechart with this series:

<mx:series>
     <mx:LineSeries id="incommingLineChartSeries1"
dataProvider="{this.incommingData.item}" yField="number" />
     <mx:LineSeries id="incommingLineChartSeries2"
dataProvider="{this.incommingPreviousData.item}" yField="number" />
</mx:series>

I have a dataTipRenderer that shows a nice dataTip. In that dataTip I
want to compare the 2 items from the lines. I want to show something
like this:

Incomming this month:
$20,000
Incomming previous month:
$10,000
+100%

This calculation should be in the dataTip so is there a way to know the
data from another LineSeries in the datatip?