I would agree with the above posts. Getting all the rust out is going to be the real trick. If rust is still there when you coat the inside of the door, I don't think it will last. Rust desolvers that bring it to bare metal first, then using an epoxy primer will give some results. I would even paint the primer.
Cold storage on cement floors is bad too. The cement sweats and holds moisture, allowing it to creep back into your project.
