I think modeling the steel is quite easy if this is just one tall column with a short beam at the top. Sounds like all you need for the support point is to model one element column.

Michael,
I'm not sure what you meant by CAESAR only considering one moment of inertia for a beam. To my knowledge, one of the advantages of using the structural modeler is that you can use two area moments of inertia for each element. And you can also rotate it to the proper orientation.