How do I add rain to the terrains?

As you all know there is a map editor in the game(pressing f11) where you can edit things in the map you play in ,
I was wondering how i could mange adding rain in? from the editor I tried adding precipitation witch had a rain like icon , I thought putting that would add rain in but it didn't do a thing.
if theres steps in how it should be done please let me know , thank you.

 

I searched and found this bit of Torque documentation.

Unfortunately, the file that contains the default rain datablock mentioned in that page (game/art/datablocks/environment.cs) has been removed from Beamng. Even pasting the file back in has failed to yield results. Perhaps someone more code-savvy than I could find out what part of Beamng's base code needs to link up to the file and datablock to allow the precipitation object to recognize the program's default.