Shadows on the terrain mesh

Hi y'all dudies!
Probably not the right forum to post this in, but...

Is it at all possible to get the shapes (DIF objects) to create decent shadows on the terrain mesh? From what I've seen so far (and I am mega-uber-n00bie right here, sorry) these objects appear to generate NO shadows on the terrain. The shadows the player creats are impressive and the actual DIF object create good shadows onto themselves, but the terrain looks fullbright sometimes, no shadows. Am I doing the mission lighting all wrong or something??? or is this an engine limitation?

Any help? = appreciated!