I think someone used silver foil and a heat gun here before, and had good results.
I actually went at mine with Testors silver model paint, a small brush and a steady hand. They came out fantastic.
Don't know if this would be helpful info, but thought I'd chime in- Just got done painting some badges for my Rocco, black background w/ white raised lettering. Used spray to paint the entire emblem white, then black acrylic to paint the background and spaces between the letters, using a wet towel to wipe the black off the letters before it dried. Kind of an experiment, but they turned out well I think