How set Stacked="true" column chart telerik - asp.net

Question

I have a column chart, so I would like to chart the values last columns show stacked values.
I am using the RadHtmlChart Telerik, but setting parameter tacked="true" in the last columns, but the result its wrong the chart is not stacked, if i set this attribute in the first line serie, the chart is stacked. This my code:
<telerik:RadHtmlChart ID="Chart" runat="server" Width="680" Height="500">
<PlotArea>
<XAxis>
<LabelsAppearance>
<TextStyle Color="white" FontFamily="Arial" FontSize="13" />
</LabelsAppearance>
</XAxis>
<YAxis Step="5000000" MinValue="0" >
<LabelsAppearance DataFormatString="${0:0,0}">
<TextStyle Color="white" FontFamily="Arial" FontSize="12" />
</LabelsAppearance>
</YAxis>
<Series>
<telerik:ColumnSeries Name="Garantías Vigentes">
<LabelsAppearance Position="Center" DataFormatString="${0:0,0}" >
<TextStyle Color="Black" FontFamily="Arial" Bold="True" FontSize="18" />
</LabelsAppearance>
<Appearance>
<FillStyle BackgroundColor="#87cb50"></FillStyle>
</Appearance>
<SeriesItems>
</SeriesItems>
</telerik:ColumnSeries>
<telerik:ColumnSeries Name="Saldo Vigente" Stacked="true">
<LabelsAppearance Position="Center" DataFormatString="${0:0,0}">
<TextStyle Color="Black" FontFamily="Arial" Bold="True" FontSize="18" />
</LabelsAppearance>
<Appearance>
<FillStyle BackgroundColor="#8DB4E2"></FillStyle>
</Appearance>
<SeriesItems>
</SeriesItems>
</telerik:ColumnSeries>
<telerik:ColumnSeries Name="" Stacked="true">
<LabelsAppearance Position="Center" DataFormatString="${0:0,0}">
<TextStyle Color="Black" FontFamily="Arial" Bold="True" FontSize="18" />
</LabelsAppearance>
<Appearance>
<FillStyle BackgroundColor="#8DB4E2"></FillStyle>
</Appearance>
<SeriesItems>
</SeriesItems>
</telerik:ColumnSeries>
</Series>
</PlotArea>
<Legend>
<Appearance Position="Bottom"><TextStyle Color="white" FontFamily="Arial" FontSize="20" Bold="True"/></Appearance>
</Legend>
</telerik:RadHtmlChart>
thanks for yours comments

Answer 1

Read this to see how to use the feature: http://www.telerik.com/help/aspnet-ajax/htmlchart-stacked-series.html.
Read this to see how to get a total in the last series: http://www.telerik.com/forums/need-to-display-grand-total-on-top-of-the-htmlchart-stacked-bars.

Answer 2

Finally I set the property stacked= true in the last column, my code:
<telerik:RadHtmlChart ID="Chart" runat="server" Width="680" Height="500">
<PlotArea>
<XAxis>
<LabelsAppearance>
<TextStyle Color="white" FontFamily="Arial" FontSize="13" />
</LabelsAppearance>
</XAxis>
<YAxis MinValue="0" >
<LabelsAppearance DataFormatString="${0:0,0}">
<TextStyle Color="white" FontFamily="Arial" FontSize="12" />
</LabelsAppearance>
</YAxis>
<Series>
<telerik:ColumnSeries Name="Garantías Vigentes" Stacked="true">
<LabelsAppearance Position="Center" DataFormatString="${0:0,0}">
<TextStyle Color="Black" FontFamily="Arial" Bold="True" FontSize="18" />
</LabelsAppearance>
<Appearance>
<FillStyle BackgroundColor="#87cb50"></FillStyle>
</Appearance>
<SeriesItems>
</SeriesItems>
</telerik:ColumnSeries>
</Series>
<Series>
<telerik:ColumnSeries Name="Saldo Vigente" Stacked="true">
<LabelsAppearance Position="Center" DataFormatString="${0:0,0}">
<TextStyle Color="Black" FontFamily="Arial" Bold="True" FontSize="18" />
</LabelsAppearance>
<Appearance>
<FillStyle BackgroundColor="#8DB4E2"></FillStyle>
</Appearance>
<SeriesItems>
<telerik:CategorySeriesItem Y="0"></telerik:CategorySeriesItem>
</SeriesItems>
</telerik:ColumnSeries>
<telerik:ColumnSeries Name="" >
<LabelsAppearance Position="Center" DataFormatString="${0:0,0}">
<TextStyle Color="Black" FontFamily="Arial" Bold="True" FontSize="0" />
</LabelsAppearance>
<Appearance>
<FillStyle BackgroundColor="#1B1A1A"></FillStyle>
</Appearance>
<SeriesItems>
<telerik:CategorySeriesItem Y="0"></telerik:CategorySeriesItem>
</SeriesItems>
</telerik:ColumnSeries>
</Series>
</PlotArea>
<Legend>
<Appearance Position="Bottom"><TextStyle Color="white" FontFamily="Arial" FontSize="20" Bold="True"/></Appearance>
</Legend>
</telerik:RadHtmlChart>
the part of code-behind:
Public Sub LoadChart()
Dim salesAuto As Double
Dim lessVig As Double
lessVig = LtlSaldoVigente.Text.ToDouble
salesAuto = CDbl(LtlLine.Text.ToDouble - lessVig * 1000000)
Chart.PlotArea.YAxis.MinorGridLines.Visible = False
Chart.PlotArea.XAxis.MinorGridLines.Visible = False
Dim ColumnSeries1 As ColumnSeries = TryCast(Chart.PlotArea.Series(0), ColumnSeries)
ColumnSeries1.SeriesItems.Add(y:=CDec(LtlValue.Text.ToDouble))
ColumnSeries1.SeriesItems.Add(y:=CDec(0))
Dim ColumnSeries2 As ColumnSeries = TryCast(Chart.PlotArea.Series(1), ColumnSeries)
ColumnSeries2.Stacked = True
ColumnSeries2.SeriesItems.Add(y:=CDec(LtlSaVig.Text.ToDouble * 1000000))
Dim ColumnSeries3 As ColumnSeries = TryCast(Chart.PlotArea.Series(2), ColumnSeries)
ColumnSeries3.SeriesItems.Add(y:=CDec(lessVig))
End Sub
the result: