your example:
terran model i listed as 0ColonyShip and minor model as 35ColonyShip. i also tried 0Ship21 and 35Ship21.
your ship file need the following prefixs and will look like this:0ColonyShip,350ColonyShip for your icon file it is the same and they are CaSe sensetive:0ColonyShip_Icon.tga,0ColonyShip_Icon24Trans.tga, 350ColonyShip_Icon.tga,350ColonyShip_Icon24Trans.tga