Texture3D stays black no matter what?


I have been trying for a while to get 3d Textures to work, but without success. I tried this code:
and this:
Unity - Manual: 3D textures but none of them worked, then I found this thread: http://forum.unity3d.com/threads/164556-Texture-3D-Problems and it seems they have the same problem as I do but no solution either. I did not want to revive a dead thread so I created this question.

My graphics card is a GeForce GTX 570 and I use the free edition of Unity 4 (4.3.2f1) and I do not get any error message.


Solved in the forums after it was burried here.

For anyone searching for this: 3D Textures are a Pro Only feature.