Building Ground Texture

How can I make the ground texture of a building (in my case a tower) to be the Purple Dalaran Tile. It isnt in one of the drop-down choices for ground textures, and I cant figure out a trigger for it. I've seen it done so I know it can be done, but I dont know how. Any1 know?

I think you have to modifiy the UberSplatData.slk, or you could reimport your model over one of the old splats. If your having probs PM chrydgod, he knows alot about that sorta thing