The internal webbrowser of the Designer is not capable of showing the Winding font. Most characters of the Winding fonts are available in Unicode though and can be applied without setting the font. Try adding the following to the Source: ✁
An overview of these characters can be found here:
Thanks Erik, you got me on the right track. This actually needed to be added to the source: ✁ you just had a $ instead of the &. By the way it does show up in the preview just as expected now.