A base coat of a medium metallic with the swirls hand painted in silver worked fine for me, see example here:
Album:Central Powers Aircraft Model Images
I used Citadel Boltgun as the darker colour with Citadel Mithril Silver for the swirls. they look a bit clumsy in 1/72, they would be easier in 1/48 IMO.
Regards,
Nigel