Under EASA if you have an Aeros rating plus either an FI or CRI rating you will be able to instruct for it. This is not scheduled to start until 2015 so there will be various mixtures of National qualifications remaining until then. There is no JAA Aeros rating and I have come across some instructors who have experienced problems with one State not accepting another State's National qualifications and even JAA qualifications. Before you start, I think you should check with the authorities in the State that issued the pilots licence because it is a real mess in this area.