Doesn't the DEF (or one of the other campaign groups) use Enigma to communicate with boats on patrol? And there is also a set of Single Missions with canned messages in Engima.
http://www.subsim.com/radioroom/down...do=file&id=400
All of these, of course, use the external Enigma Simulator.
http://users.telenet.be/d.rijmenants/en/enigmasim.htm The Simulator works well, but I have never used it "operationally" in-game.