I haven't bought it yet, but I assume it uses its own UV map to map out the textures. I'd look at the original material to see what actually fits it, and then create your own texture that fits that. However... be careful as some cutscene/move players can jump characters BELOW the terrains created.
Viewing post in smooth terrain grid pack comments
sorry it took so long to get back to you. go to 3d stamps then underneath it where it says models, find your model.
It will show a panel on the right with material 1 - in that box is a little white icon with an arrow pointing left.
this will show THAT model's material settings. in the middle of the panel on the right is where shader settings are, a)n, map_nolit, whatever, etc. that's where you can change its shader style, as well as the UV map that it uses.