that is not a mapping problem so to say, no need to recompile the map...
just unzip the file, put the missing texture files into it, zip it again into a .pk3
but use a slightliy different name for it.... means you have to edit the arena file for it, and rename all files inside the .pk3, too... (...)
ah scratch that all.
describe why the map is so good, or what is different to crossing, if i think it is worth the effort i will do it.