Once you find the folder they were created in, all you do is rename them; avatar1.dat, avatar2.dat, avatar3.dat, avatar4.dat, or avatar5.dat.
I had 3 toons on one account, and another 3 toons on a second account. I made all three of the new classes. I renamed two of them avatar4.dat and avatar5.dat. They both showed up on both accounts when I logged into the game. I renamed them on one and deleted them from the second account. When I went back to the westwood folder, there was one left. I renamed her avatar4.dat and she showed up on my second account.
Hope this makes sense and helps. If not, sorry!