Skernsk. You have to play arround with different layers. One in light grey, one in blue and one wich has some structure which makes the metal surface looking a bit "waved" (sorry, cant find the right word).
I'm working on a metallic surface right now, but i cant tell you if its accurate or not.
If there's a prof on that issue, it would be great to make and post a short "how to do" manual about.
airmess