Chart with CategoryAxis "Date axis"

Hi,
In my Code I generate a excel file with data( date and data) and a Chart.
The Chart is a LineChart with values on y Axis and Date on x Achses..
With the TCategoryAxisOptions.DateAxis in The TCategoryAxis and the min, max Value I want to tell from date to date shown in the chart...

But In the output Excel File (in Excel) the Category Axis are still "Text Axis".

Could it be, that the TCategoryAxisOptions.DateAxis is ignored?

My Code;

TFlxChartFont AxisFont = null;
                    TAxisLineOptions AxisLine = new TAxisLineOptions();
                    AxisLine.DoNotDrawLabelsIfNotDrawingAxis = false;
                    TAxisTickOptions AxisTicks = new TAxisTickOptions(TTickType.Outside, TTickType.None, TAxisLabelPosition.NextToAxis, TBackgroundMode.Transparent, null, TDrawingColor.FromSystem(TSystemColor.WindowText), null);
                    TAxisRangeOptions AxisRangeOptions = new TAxisRangeOptions(1, 1, true, false, false, true);
                    TBaseAxis CatAxis = new TCategoryAxis(44927, 44957, 0, TDateUnits.Days, 0, TDateUnits.Days, TDateUnits.Days, 0, TCategoryAxisOptions.AutoMajor | TCategoryAxisOptions.AutoMinor | TCategoryAxisOptions.DateAxis | TCategoryAxisOptions.AutoCrossDate | TCategoryAxisOptions.AutoDate, AxisFont, "m/d/yyyy", false, AxisLine, AxisTicks, AxisRangeOptions, null, TChartAxisPos.Bottom, 0, 0);
                    

                    AxisFont = null;
                    AxisLine = new TAxisLineOptions();
                    AxisLine.DoNotDrawLabelsIfNotDrawingAxis = false;
                    AxisTicks = new TAxisTickOptions(TTickType.Outside, TTickType.None, TAxisLabelPosition.NextToAxis, TBackgroundMode.Transparent, null, TDrawingColor.FromSystem(TSystemColor.WindowText), null);

                    TBaseAxis ValAxis = new TValueAxis(0, 0, 0, 0, 0, TValueAxisOptions.AutoMin | TValueAxisOptions.AutoMax | TValueAxisOptions.AutoMajor | TValueAxisOptions.AutoMinor | TValueAxisOptions.AutoCross, AxisFont, "0.0", true, AxisLine, AxisTicks, null, TChartAxisPos.Left, 0);
                    Chart1.SetChartAxis(new TChartAxis(0, CatAxis, ValAxis));