you want to make something that doesn't previously exist in the game am I right?
well at this time you cant actually do that. I take it your attempting to make your first strides in modding the game? well at the moment what we can do is create new decorative blocks that function similarly to hull, and do well, pretty much nothing but look pretty. applying functions is just at the moment unsupported by the games L.U.A. code if you don't know what that is, its a programing language, and this game is written in it and a form of Java code as well. it is planned to use the games existing function towards blocks, and applying them with custom textures, but for now it's just not possible. sorry if that puts a stop on your mod, but nothing we can do about it right now.