For a declarative view (XML, HTML) the "dot" in front of the function name is to let the view know that the formatter function can be found in the controller.
I solved this by using a factory function instead of a template to create the list items.
By using the function I was able to get the key from mainMenu model then query the i18n model using that key.
I will try your idea when I have some time to re-visit this in my application.
Thanks.