How to change the angle of anisotropic shading?

I want to use anisotropic specular highlights by checking the Tangent Shading option in the material using the Blender Internal render.
The problem is that I cannot find the setting to orient the direction of the anisotropy.
How do I do that? Is it any different in Cycles?

Blender 2.74.5

BI does not support texture-based anisotropic orientation (only orientation by UVmap).

Thank you for the reply!