Small tweak to display void on Minecraft maps as a black color, instead of transparent.

Hello, I have space map on my server. Its basically empty world and people are building space stactions/ships/etc..

Only problem is with Minecraft maps. Screenshot below explains everything:



I would like some hints or small plugin, that displays void on map as a black color. So this map picture would look completely different and much cooler.

Commands/permissions: probably none (or one for refreshing existing maps?)
Config: list of worlds enabled for this tweak
Name: BlackVoidOnMaps? Does not really matters I guess....

Thanks!