Here is what you do - make a new character normally (1st level). Save it (doesn't matter what it is, really). Now, Leto should be under Utils in your NWN folder.
Start it.
Click on Menu, and navigate to your local vault folder in your NWN install directory.
Locate the .bic that you just created (will be named whatever you named the character).
Open it.
Now you can do whatever you want with your character, accordingly.
Then, save it back to the same place (local vault).
Start your PRC mod, and pick that .bic that you modified with leto.
Have fun!