If you want to paint it, an alternative is to use POR-15 paint. Its not like an ordinary paint, and it comes out so well, you have to squint to see any paint strokes.

This paint will NEVER come off and Ive seen someone take to it with a hammer and it wont chip off.. its that hard.

Id recommend sandblasting it first but accoding to the company you can use it on rusted surfaces

http://www.por15.com/prodinfo.asp?grp=1&dept=1