thats cool
The easiest way to paint would be to use an "etching" primer , and than some spray on krylon ( the kind meant for outdoor use) ... you can also use zinccromate to prime/etch these before paint also ... with a good base, the paint will be solid. I painted the rims on my U-Flash and it was pretty durable.
best way would be to have them powder coated, but you would have to get that done by someone who has a system set up ..
Voy