Style in one column only if the cell's value is greater than 0

[romeu]

In my GridPanel, I have to set style in one column only if the cell's value is greater than 0. How can I do this? In the same column, I have a format float <Renderer Fn="Ext.util.Format.numberRenderer('.0,00 /i')" />. I try to put <Renderer Handler="if (value > 0) metadata.css = 'red-label'; return value;" />, but don't work the format float. If I apply one css Css="background-color:#FF8080;", all cells are the style. Follows my code:

<ext:GridPanel ID="grdControleCredito" runat="server" Layout="Form" StripeRows="true" TrackMouseOver="true" Height="80" AutoScroll="true">[
	<Store>
		<ext:Store ID="Store2" runat="server">
			<Reader>
				<ext:JsonReader runat="server">
					<Fields>
						<ext:RecordField Name="VlrDevidoAtrasado" Type="Float" />
					</Fields>
				</ext:JsonReader>
			</Reader>
		</ext:Store>
	</Store>
	<ColumnModel ID="ToolbargrdControleCreditoColumnModel" runat="server">
		<Columns>
                	<ext:Column Header="Vlr Dev. Atrasado" Width="110" DataIndex="VlrDevidoAtrasado" Align="Right" Css="background-color:#FF8080;">
				<Renderer Fn="Ext.util.Format.numberRenderer('.0,00 /i')" />
			</ext:Column>
		</Columns>
	</ColumnModel>
	<Plugins>
		<ext:GridFilters ID="GridFilters1" runat="server" Local="true" FiltersText="Filtro">
			<Filters>
				<ext:NumericFilter DataIndex="VlrDevidoAtrasado" />
			</Filters>
                </ext:GridFilters>
	</Plugins>
	<SelectionModel>
		<ext:RowSelectionModel ID="grdControleCreditoRowSelectionModel1" runat="server" />
	</SelectionModel>
</ext:GridPanel>