get the add on, and if you're tired of the german boats try my Jyunsen B - Kaidai -Kaichu IJN submarines mod version 2.1, you'll get 3 different types of boats, and the famous "long lance" japanese topedoes.
http://www.subsim.com/radioroom/showthread.php?t=137761
keltos
download link :
http://files.filefront.com/v+21+IJN+.../fileinfo.html
And install this patch on top of the mod :
http://files.filefront.com/UPCDataGE.../fileinfo.html
then you'll get the AA crew