Columns and Arches

[mnknute]

I am a new user of HD Suite 7.0 and am having an issue with arches and columns. I have attached a couple of photos of what I am trying to achieve. Not exactly sure of how to go about it. I have tried a couple of ways with soffits and cabinets, but no real success. The problems that I am having is that we have a vaulted ceiling and I cant get the wall above the arch to go to the ceiling. I cant figure out how to do an arch without there being wall directly below the ends of the arch.

Thanks