Adding Horizontal Axis Labels to Chart without Selecting the chart

Hello all,

the following code enables me to add data to my stacked column chart.
The horizontal axis labels however are shown as numbers (1,2,3,4...)
The column with the data that I would like to use as axis labels are in range D15:D18.
Do you know how to add these labels to the chart without selecting it.

Sub JKJKJ()
    With Sheets("CALC")
       .ChartObjects("Chart 3").Chart.SetSourceData Source:=.Range("G15:H18"), PlotBy:=xlColumns
    End With
End Sub