Hmmmm... Seems weird that adobe would not say this... Maybe I am wrong but I do not think so...
Its pretty simple... Reflow is just for CSS... So you can do anything you want with HTML... And reflow will read any handwritten CSS...
So to implement a font icon from font awesome... Using Dreamweaver or Brackets, all you would do is download or link to the kit in the head of your HTML file... Then just put the proper mark up in your HTML file where you want the icons to appear... Then load that HTML file into reflow and you should see the icons... Then just use normal class or ID selectors to target and position the icons where you want... I would probably use and <i></i> tag to put the icons in...
Font awesome has the HTML mark up here - Font Awesome Examples