The Unit property specifies the unit being used to display labels in the level. The Label property may change the Unit and the Count property. You can always use a different Unit or Count by setting the property after setting the Label property.  Changing the Label property may change the Unit property. For instance, if the user calls Label = "<%d%>", the Unit property is automatically put on exDay. The UnitScale property indicates the minimum time unit from all levels. The UnitScale property changes the Label, Unit and the ToolTip for a level with predefined values defined by the Label and LabelToolTip properties. Use the LevelCount property to specify the count of levels in the chart's header. Use the UnitWidth property to specify the width of the time unit. Use the Count property to specify the number of units being displayed in the same place. Use the NextDate property to get the next date. Use the Zoom method to zoom the chart to a specified interval of dates.

The first level displays the month, the year and the number of the week in the year , the second level displays the name of the week day, and the third level displays the day of the month. The LevelCount property specifies the number of levels being displayed, in our case 3. 

The following Template shows how to display your header using three levels as arranged in the picture above ( just copy and paste the following script to Template page ):

BeginUpdate()
Chart
{
	LevelCount = 3
	Level(0)
	{
		Label = "<b><%mmm%>, <%yyyy%></b> <r>Week: <%ww%>"
		Unit = 256	'exWeek
	}
	Level(1).Label = "<%d1%>"
	Level(2).Label = "<%d%>"
}
EndUpdate()

The following VB sample displays your header using 3 levels as shown above:

With G2antt1
    .BeginUpdate
    With .Chart
        .LevelCount = 3
        With .Level(0)
            .Label = "<b><%mmm%>, <%yyyy%></b> <r>Week: <%ww%>"
            .Unit = EXG2ANTTLibCtl.UnitEnum.exWeek
        End With
        .Level(1).Label = "<%d1%>"
        .Level(2).Label = "<%d%>"
    End With
    .EndUpdate
End With

 The following VFP sample displays your header using 3 levels:

with thisform.g2antt1
.BeginUpdate()
with .Chart
	.LevelCount = 3
	with .Level(0)
		.Label = "<b><%mmm%>, <%yyyy%></b> <r>Week: <%ww%>"
		.Unit = 256
	endwith
	.Level(1).Label = "<%d1%>"
	.Level(2).Label = "<%d%>"
endwith
.EndUpdate()	
endwith

 The following VB.NET sample displays your header using 3 levels:

With AxG2antt1
    .BeginUpdate()
    With .Chart
        .LevelCount = 3
        With .Level(0)
            .Label = "<b><%mmm%>, <%yyyy%></b> <r>Week: <%ww%>"
            .Unit = EXG2ANTTLib.UnitEnum.exWeek
        End With
        .Level(1).Label = "<%d1%>"
        .Level(2).Label = "<%d%>"
    End With
    .EndUpdate()
End With

 The following C# sample displays your header using 3 levels:

axG2antt1.BeginUpdate();
EXG2ANTTLib.Chart chart = axG2antt1.Chart;
chart.LevelCount = 3;
chart.get_Level(0).Label = "<b><%mmm%>, <%yyyy%></b> <r>Week: <%ww%>";
chart.get_Level(0).Unit = EXG2ANTTLib.UnitEnum.exWeek;
chart.get_Level(1).Label = "<%d1%>";
chart.get_Level(2).Label = "<%d%>";
axG2antt1.EndUpdate();

 The following C++ sample displays your header using 3 levels:

m_g2antt.BeginUpdate();
CChart chart = m_g2antt.GetChart();
chart.SetLevelCount( 3 );
chart.GetLevel(0).SetLabel(COleVariant( "<b><%mmm%>, <%yyyy%></b> <r>Week: <%ww%>" ));
chart.GetLevel(0).SetUnit(256);
chart.GetLevel(1).SetLabel(COleVariant( "<%d1%>" ));
chart.GetLevel(2).SetLabel(COleVariant( "<%d%>" ));
m_g2antt.EndUpdate();