You can actually just make a completely empty blocks map (or fill it with a colour) and as long as it's linked up to your .structure file, the editor will open it. You can then draw your ship using the brushes defined in your .structure file. Just make sure you make your empty blockmap big enough to fill your ship. You need to open the .rar file with WinRAR or 7zip! (or a similar utility) I've uploaded it as a .rar rather than a .zip because google chrome doesn't like my domain and won't let .zip files be downloaded properly. Hopefully I'll be able to upload future releases as .zips.