Yes...it is possible to use new team codes for custom teams...but you have to provide the game with the following graphics with file names which use your new team codes (or the game will crash).
EXAMPLE:
For creating my
Team Canada National Teams patch
1. I set the team code for Canada to "
ca" in the teams.dbf file.
2. I put my custom jersey files in the render\xteam directory and named them:
cahome.fsh
cahome_num.fsh
caaway.fsh
caaway_num.fsh
3. I placed my custom court files in the render\xcourt directory and named them:
cacrt.fsh
cacrt.o
4. I placed my custom game overlay graphics in the render\xoverlay directory and named it:
ca.fsh
There are other front end graphics that you can add like the portrait background etc. but the game will not crash if you don't have them. All the files I have listed above must be present or the game will crash when you try to play a game.
Hope this helps...