Sievenpiper Mushroom HFSS Simulation Help

Salutations!

I'm working on simulating a sievenpiper mushroom dispersion diagram on HFSS. I think my theoretical understanding is good enough, but HFSS is really causing me problems. Don't know the program that well, and cant find enough resources.

With hit and trial, and a few online guides, i managed getting decent results. That's where my problems begin, because now i need to go through this series of steps:

1) Simulate parallel plate waveguide and investigate modes (done, but only first two modes are satisfactory)
2) Simulate dielectric slab on conductor plane and investigate modes
3) Add via, patch and simulate, hence a logical progression from a simpler textbook structure to the mushroom.

Anyone who has done this, or knows enough to help me with the simulation, please come through. My email, phone number and address are all available to anyone who can help me. I live in Brooklyn, NY, maybe someone is conveniently close.
I assure you, i don't expect you to hold my hand through this. The only help i'll probably need is working HFSS in 'Eigenmode' solution setup, convergence, meshing and analysis of higher modes.

Cheers
msokey

Have you reached anything with the sievenpiper simulations? Let me know if you did please?

I'm working on the same structure but with a microstrip patch on top, but I'm getting a mixture of weird results and need some guidance...

Thanks!