It is easy I've instert samarkand / constinopole to sw client.
I guess GM can do the same.
All you have to do is to get
these files.
map_samarkand.ddj
map_constantinople.ddj
map_constantinople.ddj
city_samarkand_focus.ddj
city_samarkand.ddj
city_constantinople_press.ddj
city_constantinople_focus.ddj
city_constantinople.ddj
And edit this file.
server_dep\silkroad\textdata\worldmap_mapinfo.txt
And enable it on serverside.
those files must match to client/server version or it won't work
here is constantinopole on Sw client