Probably the same technique as suggested in the kit reviews section for dealing with the Gullwing dashboard bezels, etc. -- paint the appropriate area body color (for hubcaps, I'd punch a hole for the entire painted area in masking tape), apply paint, then gently wipe away the paint from the raised star/ring. Might work best with acrylic or other suitable paint, with a really good magnifier.
Personally, I'd rather use knockoff spinners than deal with that. Rumor has it that aftermarket Rudge wheels are on the way.