RadHtmlChart Series Category duplicates

Hi,

I am creating a chart with two ColumnSeries with X-Axis containing Date and Y-Axis containing Item count. Now I want to create a stacked chart for the two series. Below is the program i have got. When I ran this, I am getting attached Chart which has X-Axis items not overlapping. For Series2, X-Axis items are again added. Even though, I am checking for the duplicates, it is adding the x-axis item. 

I cannot use Date as X-Axis type because, it only supports Databound objects. Is there a way to achieve my desired behavior without X-Axis values overlapping?

Satish



        private void UpdateOperationsChart()
        {
            SqlDataClient prodClient = new SqlDataClient(DataSource.Prod);
            prodClient.Init();

            DataTable table200 = prodClient.GetProvisioningOperations(OperationType.SelectedText,200);
            DataTable table500 = prodClient.GetProvisioningOperations(OperationType.SelectedText,500);

            ProvisioningChart.PlotArea.XAxis.TitleAppearance.Text = "Day";
            ProvisioningChart.PlotArea.YAxis.TitleAppearance.Text = "Request Duration In Mins";

            AxisY axisY = new AxisY();
            axisY.Name = "Operation Count";
            ProvisioningChart.PlotArea.AdditionalYAxes.Add(axisY);

            ProvisioningChart.PlotArea.XAxis.Type = Telerik.Web.UI.HtmlChart.AxisType.Category;
            ProvisioningChart.PlotArea.XAxis.AxisCrossingPoints.Add(0);
            ProvisioningChart.PlotArea.XAxis.AxisCrossingPoints.Add(100);

            LineSeries durationAvgSeries = new LineSeries();
            durationAvgSeries.Appearance.FillStyle.BackgroundColor = System.Drawing.Color.Blue;

            ColumnSeries request200Series = new ColumnSeries();
            ColumnSeries request500Series = new ColumnSeries();
            //request200Series.AxisName = "200";
            //request500Series.AxisName = "500";
            request200Series.Appearance.FillStyle.BackgroundColor = System.Drawing.Color.Green;
            request500Series.Appearance.FillStyle.BackgroundColor = System.Drawing.Color.Red;

            foreach (DataRow row in table200.Rows)
            {
                //durationAvgSeries.SeriesItems.Add(Decimal.Parse(row["AvgDurationInMin"].ToString()));
                request200Series.SeriesItems.Add(Decimal.Parse(row["OperationCount"].ToString()));
                AxisItem xAxisItem = new AxisItem(Convert.ToDateTime(row["Day"].ToString()).Month + "/" + Convert.ToDateTime(row["Day"].ToString()).Day);
                if (!ProvisioningChart.PlotArea.XAxis.Items.Contains(xAxisItem))
                    ProvisioningChart.PlotArea.XAxis.Items.Add(xAxisItem);
            }

            foreach (DataRow row in table500.Rows)
            {
                //durationAvgSeries.SeriesItems.Add(Decimal.Parse(row["AvgDurationInMin"].ToString()));
                request500Series.SeriesItems.Add(Decimal.Parse(row["OperationCount"].ToString()));
                AxisItem xAxisItem = new AxisItem(Convert.ToDateTime(row["Day"].ToString()).Month + "/" + Convert.ToDateTime(row["Day"].ToString()).Day);
                if (!ProvisioningChart.PlotArea.XAxis.Items.Contains(xAxisItem))
                    ProvisioningChart.PlotArea.XAxis.Items.Add(xAxisItem);
            }
            
            ProvisioningChart.PlotArea.Series.Add(request200Series);
            ProvisioningChart.PlotArea.Series.Add(request500Series);            
            //ProvisioningChart.PlotArea.Series.Add(durationAvgSeries);

            request200Series.Stacked = true;

            request500Series.Name = "500";
            request200Series.Name = "200";
            durationAvgSeries.Name = "AvgDurationInMin";

            prodClient.Close();
        }