Pedro,
I have tried both acrylics (silver +Tamiya smoke over it) and various enamels on resin figures with ok results. Best representation of metal that I have come up with is actually a base of dark silver printer's ink with subsequent highlighting with lighter and lighter shades ending up with pure silver as the lightest color. I use similar process for brass or copper metalwork and for weapons as well.
Since I treat both metal and resin figures with white primer (Citadel Skullwhite) I use this "metal" painting techinque on both. The advantage of using printer inks is their natural pigment component and fluidity (not sure if that's the right word ).
Hope this helps a bit,
Cheers,
A.
Pedro,
In addition to the advice already offered, I suggest you consider Vallejo acrylic metallics. They are very fine grained, the absence of which causes an unrealistic finish. They have several metallic colors which cover all needs. And do NOT apologize for asking questions; that is what we are here for@ --Steve Scott