multi plate capacitor in hfss

Hi,

i'm new in hfss and i have a small Problem:

i want to simulate the electric field of a multi plate capacitor.
first plate on -2600V, than a gap of 3 mm air
second plate on -1350V with holes every 0.8 mm, than a 0.3 mm epoxy gap
third plate on 0V also with holes every 0.8 mm, than a gap of 3 mm air
forth plate on -150V

I now need the electric fied in the hole area between plate one and four. All voltages are direkt voltages. I don't know if i have to assigne boundaries and how to solve this.

I hope somebody can help me.