Finding Button an Ability is bound to

[Tullamore]

Greetings
I was wondering if there is a way to find out which Button a certain Ability is bound to. Say, I would like to find what button(s) I have 'Battle Shout' bound to. Is there a way to iterate through all buttons and use an API method to find out what ability is bound to it?

(All I see is GetActionText(slot) which will only return a value if I have a macro bound to it, or GetActionTexture(slot) which will return the texture (icon) assigned to a button - which is pretty unreliable, since textures used for abilities can also be used for macros).

Thanks in advance