Has this been previously painted? If so the best paint specification is to rub down, undercoat and finish with gloss. Satin and low sheen oil paints are generally intended for indoor use and won't last very long or weather well when exposed to the elements. You can check out the Dulux, Fleetwood or Crown website for further confirmation. The trick to using oil paints and avoiding mess is to use good quality brushes, wear latex gloves (clean up is so much easier) and apply the paint using proper technique.