Are you making a single-player map? Elevators are only usable in sp specific maps like lost and level9.
As for getting it to show up in the local offline maplist, I would say you're just better off using /showcustommaps in-game. If you're serious though, look for the menu.cfg in data. Not far from the top in the menu.cfg is a list of maps for specific gamemodes, like ffamaps1 and spmaps. Just add the name of your map to the appropriate list of the gamemode the map was made for.