There are many available tools that are shipped with Symantec. One of which is the "Reset password" batch file.
This batch file, injects (manipulates) directly the database structure and renames the User: "Admin" and changes it's password back to "admin".
If this can be accomplished, than a script to inject users into the same table must be able to be accomplished.
Symantec Technical Support may not be able to indicate how to do this, but there is a way.
The Tables themselves are not easily manipulated and I wouldn't recommend you doing this unless you know what you are doing, but I am sure product development or an experience DBA could help you out on this one.