normals won't show up on terrain

hello all, i have created a nature->terrain->diffuse specular material and attached it to my terrain. i have added terrain textures with both diffuse and normal maps (the normal textures are specified as "normal" and not "texture" convert from greyscale is turned off) normal textures work just fine on all the other objects in the scene, just not with the terrain. i have tried adding more lights, increasing the texture strength, playing with the material's spec and shininess values, but nothing works. any ideas?