In the brush attributes, there should be an attribute called 'tubes." Make sure it's ticked or you won't be able to define any turbulence settings. The Turbulance attributes are below it in the attribute editor under behavior. I just tried it and it works. PaintFX strokes need to be tubes or you could probably also do it by converting paintFX to poly but I haven't tried that. Hope this helped some.

I've attached a small playblast of my test.