i sand blasted mine, then primed them and then painted them, they turnd out great

We do powdercoating where I work and I can assure you plain enamel paint sticks OK to powdercoat, in fact we often use it to touch up if the paints a bit thin. I painted my wheels with thin coats from a spray can, the main problem you get orange peel due to oil wax contamination, just use lots of thin coats.  

Regards Charlie