Using Signwriter with the navigation menu

I'm simply trying to use Signwriter to replace the font of my navigation menu. It's documented how do replace content within in a node, it's a checkbox to replace headings and such but i can figure out how to replace the navigation.

I searched around, found others having problems but couldn't find any fixes that worked for me. All the workarounds i found where for older versions of drupal and my PHP knowledge is not good enough to convert a workaround to work me.

I'm assuming I'm not the first one to ask the question but can somebody point me in the right direction.

Thanks