Hi Michael X
That's easy to do, these are custom terrain shaders.
1) make a new map under \files\terrainbank f.e. industrial (will show in terrain editor Tab Tab )
2) copy all dds files from f.e. \files\terrainbank\desert in your files\terrainbank\industrial, now mod the files with the textures you want and save them as dds again keeping the name conversion.
f.e open \terrainbank\industrial\path_D.dds >>edit it and save (overwrite).
You can use the nvidia plugin for Photoshop b.t.w. or if you have 3DS max there are max scripts to do the dds baking.
There are otherways to do it but this keeps your defaults save and the work flow is fast.
Hope this helps
HP Z820 Workstation, 2 X 8 Intel Xeon E5-2665 processor
64GB DDR3-1333, nvidia geforce gtx 660