Home Directory Drive Letter logon change

Does anyone know how to change the home directory drive letter in a user’s profile using a logon script. I have tried ‘net use x: /home’ and ‘net user %username% /homedir:\\server\%username%$ /domain’ (which creates a Z drive letter) both will notchange the home directory letter in the users profile. What I wish to do is change all of our external user’s (125 of them) home drive letters