How to simulate anisotropic PhC structure using Bandsolve?

Let's take a example, a 2D (x-z plane )phonic crystal structures with air holes in the high dielectric index materials, then all the holes are filled with LC( liquid crystal), and the ordinary and extraodinary refractive indexes of LC are No=1.5, and Ne=1.7. When external electric field is applied along the y direction ,the refractive indexes in the x, y, and z directions are given by Nx=No, Ny=Ne, and Nz=No, so in this case, an isotropic material simualtion with refraction index No is valid. But on the other hand, when the electric field id applied along the z direction, those index are Nx=No,Ny=No,and Nz=Ne, respectively. So in this case, there is different refractive index betwwen in x-direction and z-direction of x-z plane, How can I simulate it ? The equivalent isotropic simulation does not work. Certainly, the structure has bandgap with TM polarization in Rsoft software.