Might consider powder coating it. Check with your local auto body shops and see if they have a preferred place to get that done. I'd think it would be tougher and last longer than paint. The powder coater can tell you if the galvanization is a problem. There is one here: http://findarticles.com/p/articles/mi_qa3698/is_199901/ai_n8846904/
http://www.superpages.com/bp/Wichita-KS/Bob-Eisel-Powder-Coatings-Inc-L0132737300.htm
http://www.superpages.com/bp/Wichita-KS/Bob-Eisel-Powder-Coatings-Inc-L0132737300.htm