I am using the example from the VB.net 2005 WebApp_Vb samples to create an image on a web page.  but when I use the following:

If fc Is Nothing Then
           fc = New FlowChart()
           fc.MeasureUnit = GraphicsUnit.Pixel
           fc.DocExtents = New RectangleF(0, 0, 600, 400)
           fc.BackColor = Color.Transparent
           fc.SelectAfterCreate = False
           fc.SelHandleSize = 6
           fc.BoxStyle = BoxStyle.Rectangle
           fc.ArrowHead = ArrowHead.BowArrow
           fc.ArrowHeadSize = 15
           Me.Session.Item("fcx") = fc
       End If

I get a black picture instead of a truly transparent picture.. ?  Any thoughts on fixing this?