Hi Gerald,

I suppose you wish to achieve a result as at the attached image. I've reached it using custom label and formating X label value (see http://help.infragistics.com/Help/NetAdvantage/NET/2008.1/CLR2.0/html/Chart_Customize_Labels_Using_the_IRenderLabel_Interface.html). In order to have datetime value at the X axis instead of column name I've set UltraChart's property SwapRowsAndColumns to true.The code is below.

 
    public class MyLabel : IRenderLabel
    {

        #region IRenderLabel Members

        public string ToString(System.Collections.Hashtable context)
        {
            string value = context["SERIES_LABEL"] as string;
            if (value != null)
            {
                DateTime dateTime;
                if (DateTime.TryParse(value, out dateTime))
                {
                    return dateTime.ToString("yyyy-MM-dd");    
                }                
            }
            return string.Empty;
        }

        #endregion
    }

 and form load event handler.

         private void TestCustomLabelForm_Load(object sender, EventArgs e)
        {
            DataTable table = new DataTable("Data");
            table.Columns.Add("Price", typeof(double));
            table.Columns.Add("Date", typeof(DateTime));

            table.Rows.Add(45.50, DateTime.Now.AddDays(1));
            table.Rows.Add(145.50, DateTime.Now.AddDays(2));
            table.Rows.Add(245.50, DateTime.Now.AddDays(3));
            table.Rows.Add(345.50, DateTime.Now.AddDays(4));

            ultraChart1.Data.SwapRowsAndColumns = true;
            ultraChart1.DataSource = table;

// register custom lable for formating tooltip data
            Hashtable hashtable = new Hashtable();
            hashtable.Add("MY_LABEL", new MyLabel());
            ultraChart1.LabelHash = hashtable;

// use the custom label
            ultraChart1.Tooltips.FormatString = "<MY_LABEL>:\n<DATA_VALUE:#,##0.00>";

// format X axis' label
            ultraChart1.Axis.X.Labels.ItemFormatString = "<ITEM_LABEL:yyyy-MM-dd>";
        }