Easiest method would be to use a table (dirty, but easy). How I do it is make a table, one side has a sidebar cell, and the other cell is the UBB; then I take and add all of my content for the table in the header and footer includes, with the area where the UBB should be being the split (table start to the td open (for the ubb) in the header, then td end (for the ubb) to the table end in the footer.
You can see this in action
here.
