samba with winbind and win 2k active directory

i am using samba with winbind in redhat linux with security = domain
in smb.conf however a windows client can access a share in the samba server only if the samba
server name is added in the logon to restriction option in the Win 2k
Active Directory.
For example: username john can login only to computer ALPHAONE, he
can only access the samba share if i add the samba server name for ex.
SAMBA in the list of the computers he can logon to. Any suggestions on how to bypass this?