[mkgmap-dev] How to display administrative boundaries / shade them?

Hi mkgmap folks -- sorry if this is kind of a beginning question, but I can't for the life of me figure out how to get administrative boundaries (or really any arbitrary polygon) to display with mkgmap. Ideally I'd be able to lightly shade the inside of the boundary polygon, but even displaying the polygon is eluding me. An example OSM relation that I'm trying to display is Conyers, GA, USA relation ID 119584. I understand that there might be editing necessary to the style files, but it's not really clear: do I edit relations, lines, or polygons? Or all 3? Can anyone offer any tips? Thanks, Craig