i think its possible - i managed to extract .ddsx textures (from "vegetation" pack - changed to .dds file and edit in Photoshop) and edit them (or replace with empty ones) but still i cant find a program/code to compile changed .ddsx files to this "vegetation" file)
thus i cannot test how its works...
PS. this works well on WoT game and its much more easy because "mods" folder included in WoT ;]