Elevator walls read the story heights set in the file story heights. As there is no way to manually set these heights in the elevator settings box, you must turn off the Show Wall option. Construct the walls of the elevator core as you would any other wall.
You may want consider having this building in a separate file and hotlinking it in as the different story heights may cause you other problems. This won't resolve the elevator problem you have as once hotlinked in the elevator would still read the story heights of the host file.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"