Can transparent textures used as func_illusionaries(like low grass, bushes, tree leaves) be made darker within Hammer to work in dark places, or do I have to darken the texture itself with Wally or something? Cuz I have some caves with vines floating in them and the vines glow in the dark(not producing light, but you can see the vines as if they were in the light_enviroment's view).

I have also had this problem. I think its because when a texture is transparent, it needs to be a func_wall

Func_wall's are ENTITIES, which, are not affected by light in DoD, another words, they will look bright and will NOT cast shadows.

I believe your outta luck dude, unless someone has a trick up there sleeve.

someone confirm or deny this plz.

Voodoo