Yes, you can paint your door but first take into consideration that the warranty will be null and void once you paint them and if damage is done to your door and a panel needs to be replaced you will likely need to repaint the entire door due to the UV rays fading the paint you used. This is due to not being baked on as it is in the factory. Upon saying this your residential and commercial overhead doors can be painted with any high quality exterior latex paint. Do not use an oil based paint. Please consult your paint store for which exterior latex paint is recommended for the surface on your overhead door.
Painting instructions: Remove the weather stripping from the sides & top. Rub the exterior with a Scotch-brite fiber pot-scubber to dull the surface a bit. You can buy the pot-scubber at Loblaws, Zehrs, No-Frills etc. Do NOT use steel wool. Then wash with a diluted trisodium phosphate (TSP) solution (Home hardware or CTC); rinse and let dry. Then apply a good acrylic latex paint in the shade when the door is cool. If you paint in the sun when the door is hot, the paint dries almost instantly. It doesn’t have a chance to “level” between brush or roller strokes and bubbles may harden in place. Paint the joint between the top of one section & the bottom of the one above it, with a very thin coat, allowing it to dry before the sections contact each other. Lift the door gradually to get access to this joint, as it goes around the curve at the top of the door. Re-attach the weather-stripping after a day, using the same pieces lined up with the same screw holes. If the weather-stripping is attached too soon, it will stick to the soft paint and may peel off when the door is opened.