[zipzapp]

Grmps. I don't know what happens there. Try leaving the fmb and start the mission via online play/coop.

There is no need to redo the missions from the scratch, just change the entry

MAP zip_alpen/zip_alpen_load.ini (or what ever may be written there)

in the [MAIN] setion of the .mis file in the missions (sub-)folder to

zip_Alpen/zip_Alpen_east_load.ini

or .../zip_Alpen_west_load.ini.