Animation Event (Function not supported) for a public overridden function

Previously I was using a public void method in conjunction with the animation event system with good success. But having refactored some scripts and altered the method so that it overrides an abstract method in a its parent class, the animation event no longer offers me the use of my method as before... Am I not allowed to use overridden methods for such a thing?

Interestingly, the older objects that already had the method selected, and consequently display: "Function not supported" - the call still works fine when I run the game...