i had downloaded the palette file before and i found difficulty in determining which palette to use for the cameos so i use both the adobe photoshop 7.0 and paintshop
however, you can edit the shp files by converting them to .pcx file format, if you want to edit a building you might use the copy n' paste technique, to copy a file, highligh it by using the 'maruee' tool, press CTRL+c to copy it, CTRL+v to paste it, use the 'magic wand tool' to bind your copied pic. with the base image, you know maybe delete its background.