I have been fighting to get the F-01406A-L bulkhead to install. I have not been able to get it to fit. It hits in the bottom preventing it from going under the baggage compartment ribs. Section 30 page 4 step 1.
I remember this being a little fussy getting the rear empenage and the fuselage lined up correctly. I would go back through and make sure that all of your dimples where the join happens are nesting into each other perfectly. A slight misalignment can cause problems. Good luck..