Not gonna matter if u can edit the map. The maps are checked just like attributes, therefore you can't edit them, or rez opk would have been 100% way too easy.
Making maps is easy though, make the map in an old copy of 3ds max or maya.
Export it with the lithtech world exporter plugin.
Open it in a Lithtech Jupiter EX Dedit, edit/add spawn points for fireteam or character spawns, gun spawns.
compile it to lta
Use the lithtech jupiter ex model packer to package the map and you have a custom map
That's outrun it lightly.