Texture3D stays black no matter what?

Hi,

I have been trying for a while to get 3d Textures to work, but without success. I tried this code: http://forum.unity3d.com/threads/148605-Unity-4-3D-Textures-%28Volumes%29 and this: http://docs.unity3d.com/Documentation/Components/class-Texture3D.html 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.

greetings, FTC