@Ixp Got you, alas I was hoping there was a more efficient method, since that means a lot of copy pasting code between buttons in my case.
@Jon or @Leo Nothing crucial, but as a minor suggestion for improved usability: Seeing that you can copy/paste buttons between Customize > context menu and Toolbars, I think it's logical to assume you'd also be able to do so between File Types > Context Menu and the Toolbar.