Steema Teechart VB net line serie pointer issues

Question

I am using Teechart .net from Steema, I tried to create a line serie with visible pointers, but I can't succeed in doing this.

At series creation, I do :

  TChart1.Series.RemoveAllSeries()
    Dim Line1 As New Steema.TeeChart.Styles.Line(TChart1.Chart)
    Line1.Title = "T_up_min"
    Line1.Pointer.Style = Steema.TeeChart.Styles.PointerStyles.Diamond
    Line1.Pointer.VertSize = 50
    Line1.Pointer.HorizSize = 50
    Line1.Pointer.Visible = True

But no way, the pointers are not visible...How can i do ? Note: when creating a point serie, this works fine...

Thanks !