I guess you have the Mac AppStore version.
You can easily change the names by downloading the demo from here : http://www.managames.com/predownload_en ... ac_bpi.zip
Then launch TeManager from the AppStore and find the "Mods" folder : click on "See Profile Folder" in the Save/Load menu of the game, and then go up 2 ranks in Finder.
Then take "Data\Players.Ini" from the demo and put it in a newly created folder like that "Mods\MyMod\Data\Players.Ini" .
Then launch the game again and it should be ok.