You can paint your steel siding. But the best thing you can do is go to a regular paint store, one which just sells paint, not a big box outfit. Tell them what you have and what you want to do. They should be able to point you to the right kind of primer/sealer and paint that will work best of the pre-finished steel.

But, painting it will invlove pressure washing the surface, then priming/sealing, then painting.

That's the trouble with these advertised "never paint again" products....you CAN choose to never paint again, if you don't care much about how it looks....

A roof CAN be your friend