Problem with FontSizePropertyProperty

[Ottokranz]

Is the DependencyProperty FontSizePropertyProperty actually working?
I created a FrameworkElementFactory based on the WpfHtmlControl and try to set the FontSizePropertyProperty, but the Fontsize doesent change. Binding to HtmlProperty works fine

FrameworkElementFactory factory = new FrameworkElementFactory(typeof(Html));
factory.SetValue(Html.FontSizePropertyProperty, 20d);
factory.SetBinding(Html.HtmlProperty, mb);