And you can also use number 6+ to effectivly create new styles, the only problem being that it won't display in the race set-up screen.
You can get by this by writing it into a race config file manually (the files in you My Documents/GalCiv2 for playable races, the raceconfig.xml for AI races) and then set the file to read only to prevent the game from resetting it.
I've done this to spread out the ship styles a bit more, creating an Arcean style that contains only one of each human style hull (one tiny hull, one small hull etc).