Get RenderBeginTag HTML to show in Design Mode

[Mark S]

Hello,
I can't get any rendered HTML to appearing in the designer. It doesn't give
a compile error, and it even appears fine in the browser.

I'm using the RenderBeginTag and RenderEndTag methods of the
WebCustomControl, such as:

public override void RenderBeginTag(HtmlTextWriter writer)
{
base.RenderBeginTag (writer);
writer.RenderBeginTag(HtmlTextWriterTag.Hr);
}

Does anyone know why - perhaps I need to add an attribute somewhere?

Thanks,
Mark