[Samba] prevent "delete user script" to delete special Samba user

[Niels Peuyn]

Hello,

OS: FreeBSD 6.1
Samba: 3.0.23c

What kind of exit code do the "delete user script" need, to 
prevent Samba from deleting a user in tdbsam database?

I'm testing Windows "User Manager for Domain" (usrmgr.exe) and 
I'm trying to convince Samba to NOT delete special users like
"administrator" etc.

Whenever I delete such a user within User Manager for Domain
the unix user is still in passwd, but the Samba user has been
deleted.

Thanks in advance
Niels