[Flex]Rodapé em DataGrid

<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
					   xmlns:s="library://ns.adobe.com/flex/spark"
					   xmlns:mx="library://ns.adobe.com/flex/mx"
					   minWidth="955"
					   minHeight="600"
					   creationComplete="application1_creationCompleteHandler(event)">
	<s:layout>
		<s:VerticalLayout/>
	</s:layout>
	<fx:Script>
		<![CDATA[
			import mx.collections.ArrayCollection;
			import mx.collections.Grouping;
			import mx.collections.GroupingCollection2;
			import mx.collections.GroupingField;
			import mx.collections.SummaryField2;
			import mx.collections.SummaryObject;
			import mx.collections.SummaryRow;
			import mx.events.FlexEvent;
			import mx.utils.ObjectUtil;
			[Bindable]
			public var collection:ArrayCollection=new ArrayCollection([{ loja:"Centro",vendedor:"Renzo",valor:12.22,estimativa:10 },{ loja:"Centro",vendedor:"Edinei",valor:12.22,estimativa:10 },{ loja:"Centro",
					vendedor:"Renzo",valor:11.22,estimativa:9 }]);
			[Bindable]
			public var groupCollection:GroupingCollection2;

			protected function application1_creationCompleteHandler(event:FlexEvent):void {
				var groupping:Grouping=new Grouping;
				var groupingField:GroupingField=new GroupingField("vendedor");
				var summaryRow:SummaryRow=new SummaryRow;
				summaryRow.summaryPlacement="group";
				var summaryField:SummaryField2=new SummaryField2("valor");
				summaryField.label="soma";
				summaryRow.fields=[ summaryField ];
				groupingField.summaries=[ summaryRow ];
				groupping.fields=[ groupingField ];
				groupCollection=new GroupingCollection2
				groupCollection.grouping=groupping;
				groupCollection.source=collection;
				groupCollection.refresh();
			}

			private function objFunc():SummaryObject {
				var obj:SummaryObject=new SummaryObject();
				obj.summary=true;
				return obj;
			}

			private function labelFun(obj:Object):String {
				trace(ObjectUtil.toString(obj));
				return "label";
			}
		]]>
	</fx:Script>
	<fx:Declarations>
		<!-- Place non-visual elements (e.g., services, value objects) here -->
	</fx:Declarations>
	<mx:AdvancedDataGrid dataProvider="{collection}">
		<mx:groupedColumns>
			<mx:AdvancedDataGridColumn headerText="Loja" dataField="loja"/>
			<mx:AdvancedDataGridColumn headerText="Vendedor" dataField="vendedor"/>
			<mx:AdvancedDataGridColumnGroup headerText="Vendas">
				<mx:AdvancedDataGridColumn headerText="Valor" dataField="valor"/>
				<mx:AdvancedDataGridColumn headerText="Estimativa" dataField="estimativa"/>
			</mx:AdvancedDataGridColumnGroup>
		</mx:groupedColumns>
	</mx:AdvancedDataGrid>
	<mx:AdvancedDataGrid dataProvider="{groupCollection}">
		<mx:columns>
			<mx:AdvancedDataGridColumn headerText="Loja" dataField="loja"/>
			<mx:AdvancedDataGridColumn headerText="Valor" dataField="valor"/>
			<mx:AdvancedDataGridColumn headerText="Estimativa" dataField="estimativa"/>
			<mx:AdvancedDataGridColumn headerText="Soma de Vendas" dataField="soma"/>
		</mx:columns>
	</mx:AdvancedDataGrid>
</s:WindowedApplication>