iconset in vsto does not work (excel conditional formatting)

Question

I could add an icon conditional formatting but get the circles instead of the arrow which I try to change with the iconset line but nothing happens

VBA portion id .IconSet = ActiveWorkbook.IconSets(xl3Triangles)

        With customerYearRng
            .FormatConditions.AddIconSetCondition()
            .FormatConditions(1).IconSet = Excel.XlIconSet.xl3Arrows


            With .FormatConditions(1).IconCriteria(2)
                .Type = Excel.XlConditionValueTypes.xlConditionValueNumber
                .Value = 0
                .Operator = 7
            End With
            With .FormatConditions(1).IconCriteria(3)
                .Type = Excel.XlConditionValueTypes.xlConditionValueNumber
                .Value = 0
                .Operator = 5
            End With
        End With