Here is a picture from the exterior.
It looks like they would supply everything that you need and all you would have to do is trim the molding on the post to allow them to slip in to the post. That would be easy enough with a multi saw after you know the exact size to remove.I found this example of an Eze Breeze install on Google. The columns are round but I think the concept is the same. I had already thought about centering the framing on the columns but not sure how they created such a seamless look. Thinking either trying to cut the trim just enough to flush mount the framing or would I be better off trying to use a jigsaw to try and match the profile of the trim and then caulk as needed?