FGL requires us to disable ads :/
Last time I checked, FGL was not an html5 publisher, but a middleground, you give your game to them, with their own api implemented (they have a plugin for that on C2), and they help you sell it to publishers, give you advices, and will transform their API to the publishers' API (not sure they even pay upfront anymore, as really it was just a way of promoting).
Due to that nature, any other addvertisement method is of course not interesting to them.