Using Smoothness map on unity terrain??

Hi, i find myself in need of using my smoothness map from substance designer with unity terrain but i don't know how to do so.

This is the substance, i need puddles on my terrain.

 

should work fine with standard shader or alloy (configure substance to export to the correct target).

If you don't have a decent probe or skybox you won't see anything because it can't reflect anything.

 

Question, were would i put the smoothness map?(Alpha?) I'm not using the .sbar file. I am exporting as bitmaps. Is this not ideal?