Anisotropic materials

Is there a way to model anisotropic materials using PrePoMax?
I recently found out that CalculiX supports this.

I am especially interested in modelling single crystal materials, like silicon:
http://silicon.mhopeng.ml1.net.user.fm/Silicon/Hopcroft_Youngs_Modulus_Silicon.pdf

At the moment, PrePoMax user interface only supports isotropic materials. In order to add orthotopic or anisotropic elastic material properties, one must use the CalculiX Keyword Editor: Model->Edit CalculiX Keywords. Using the editor, any CalculiX keyword can be entered into the model.