VBA code for fill color and transparency in a 3 series line chart with only one series as an area series

[travellerva]

I have VBA code for creating a line chart with 3 Series - 2 of which are lines and the third is an area line with fill below the line to the axes. Although (I think) I specify the RGB color for the fill area, it always comes out grey. Any changes to my RGB codes have no effect. Can someone help me correct my VBA code so I can define the color and transparency of the fill area. The following is the code I'm using now (subroutines called are just to create each SeriesCollection).

 Sheets("Chart").ChartObjects("Chart Portfolio").Activate
    
    Call AddNewSeries("SJM Benchmark", BenchmarkValues, DateRange, 1.5)  '(last parameter is line width)
        ActiveChart.SeriesCollection(1).Select
        With Selection.Format.Line
            .Visible = msoTrue
            .ForeColor.RGB = RGB(0, 128, 0)
        End With
    
     Call AddNewSeries("SPY", SPYValues, DateRange, 1.5)
        ActiveChart.SeriesCollection(2).Select
        With Selection.Format.Line
            .Visible = msoTrue
            .DashStyle = msoLineDash
            .ForeColor.ObjectThemeColor = msoThemeColorText1
            .ForeColor.TintAndShade = 0
            .ForeColor.Brightness = 0
        End With
        
        Call AddNewSeries("SJM Portfolio", SJMPortfolioValues, DateRange, 1.8)
        ActiveChart.SeriesCollection(3).Select
            With Selection.Format.Line
                .Visible = msoTrue
                .ForeColor.RGB = RGB(255, 0, 0)
            End With
            With Selection
                .Format.Fill.ForeColor.RGB = RGB(0, 128, 0)
            End With

I only want the 3rd line to have area fill. I note that that line must be the last one specified, else any subsequent line is also filled, but I can live with that.

Many thanks.