It's not possible to start your own World at War maps, those are only able to be system generated. One of the main reasons is that alliances hold at max 20 members; World at War maps hold 100 players.
It's also not possible to change the speed of your own maps.
However, if you are looking for maps with more speed, try a tutorial map or wait for a 4x Speed World at War map. They can be found in the Events column.