Probably, because it has .System in it's internal file structure doesn't it? So i don't think you're stuck with just gmapsupp.img in SD's Garmin folder and can use 'any_name'.img in Map root folder on it.
zumo220 is closely related hardware to nuvi5x0 [5x0 is just w/o BT] but i'm not gonna convert my [Only registered and activated users can see links. ] to validate your not wanting to bother to try it yourself [nuvi500 itself doesn't have .System]... [mumble grumble .. lazy bl**dy continentals] ... didn't the Kiwis teach you self-sufficiency?
They're a fairly resourceful lot in NZ usually.