I have the same problem, but just yesterday I found out a friend of my wifes has a FOWLR tank and he says it consumes all sorts of algae. While that doesn't really help my tank, I at least know that as I pull the eveil caulerpa from my tank, it will go to feed someone elses fish... He claims his tank inhabitants eat chaeto as well.
You can also try shading the stubborn caulerpa spots so that they get no light...
V