To be safe, I would scuff the enamel, shoot a coat of epoxy sealer, then you can shoot the eurathane. The only problem you might have with the eurathane is the reducer you use in it. It might check the enamel.

Frank


No better smell than that of fresh paint. I've been building and painting cars/trucks for 47 years. Not gonna stop now.
http://www.coxcustomcars.com/