I would not recommend an inkjet printer. The inks are not light fast and will fade over time. Even the UV (or pigmented) inks are not stable beyond a few years. If you must print on it I would recommend you find a large format print company who can either screen print or has a UV curable printing system (not the same as the aqueous UV inks mentioned earlier). A UV curable ink is much like epoxy resin and is cured with UV light rather than a catalyst. They can print on nearly any surface and are very durable. Brand names for these printers are: Durst Rho, Vutek, Gerber, Ghandi, Arizona to name a few.
Those who say it cannot be done should stay out of the way of the people doing it.