Help!!!

Ok, my problem is as such. I carry around a flash stick (spare hard drive) from school to home, and carry my maps for bolo around on it. Recently I got winbolo, and these maps from the mac version worked on it, but changed the format of each file when I saved it to windows format (ex. [Filename].MAP) and since then, they dont show up as maps for the mac version. What is the correct format for macs, if there is one, and if not, is there another way to fix this?