According to the docs for the spinner feature all that is required is a string with the content and a <span> element inside the <a> that contains the tab title. When testing this on jsbin the spinner text simply remains appended to the tab title, see example here: http://jsbin.com/evulo3/4/
Ran into this on a production app that was using 1.3, we upgraded to 1.4.2 and all the code worked except .toggle('normal'); which lost the previous functionality of showing/hiding the element with a transition and now doesn't do anything. Tested in the app and in isolation in a couple browser to make sure I wasn't doing something stupid :P