The shell cheats require additional text files to be generated and added to the root level of the build.

zz_autobahn.cfg - Makes foreign cars selectable in multiplayer.
zz_airlift.cfg - Modifies the Load Mission window so that you can load any mission. Requires an existing saved game to exist.
zz_creditline.cfg - No cash limit in the trip missions. You can buy anything that is currently available.