I had to modify the smb.conf file in the /etc directory, rather than the templates-custom and it worked for me. Am using SME 6.0.1.
I had a client that I migrated from Red-hat to SME as I wanted to setup internet gateway, email and VPN-access - it's so easy with SME. They had an existing folder on their RH server with no password access but read/write provileges, so wanted to preserve the client experience - after all, they are car mechanics, not computer techs !!
Client machines are win98 & winXP.
Addes/modified the following as per the previous article reference.
guestOK (should be "yes")
mapToGuest (should be "bad user")
globals (add "null passwords = yes")