I think TheRifle already said he applied the shader to a brush, not a patch.
Also, what Warrior says about patches and their 'nonsolid' status is untrue. All plants on Sokolov's Space are made out of patch meshes, and are fully nonsolid from every angle of approach.
The problem must lie elsewhere...
to be continued, I hope!
[EDIT] I am not sure, but for a brush to be fully nonsolid, shouldn't it have a 'nonsolid' surfaceparm applied to all of its faces? And if so, did you do that?