HELP!!!! Skinning Terrain

How can I skin, and replace the terrain with my own?

Like dirt looks like inside a space ship for example :(


(What I know)
I extract the tile from wc3 viewer
Modify it
Resave it as Blp
Get the right path and place it on world editor.
Nothing happends

Extract the terrain tiles from the mpq and skin them like a regular skin.

Why wont it show ingame? or in World edit?

I have seen this done in a map, the Peppers Multiplayer Chess map. It has a custom terrain of a chess board. So this can be done some how and he knows how. :\

You have to do what mantis said, ask Phoenix-IV for the specifics.