Multiple ASP.Net AJAX Charts on same page not working

Hello,

This is my aspx code :

<center>
                <cc1:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
                </cc1:ToolkitScriptManager>
                <cc1:LineChart ID="LineChart1" runat="server" ChartHeight="300" ChartWidth="450"
                    ChartType="Basic" ChartTitleColor="#0E426C" Visible="false" CategoryAxisLineColor="#D08AD9"
                    ValueAxisLineColor="#D08AD9" BaseLineColor="#A156AB">
                </cc1:LineChart>
                <br />
                <cc1:BarChart ID="BarChart1" runat="server" ChartHeight="300" ChartWidth="450" ChartType="Column"
                    ChartTitleColor="#0E426C" Visible="false" CategoryAxisLineColor="#D08AD9" ValueAxisLineColor="#D08AD9"
                    BaseLineColor="#A156AB">
                </cc1:BarChart>
            </center>

but when I added the bar graph, the first chart appears but does not show the lines and the second graph is not displayed at all ... Is it possible to put 2 chart like that ?

Thanks