Lotus Protector for Mail Security comes with a default configuration "Online Domino Directory". However this default configuration is preconfigured to lookup users Internet-Addresses and Internet-Addresses from groups.

If you like to extend the configuration to lookup Internet-Addresses for Mailin-Databases as well, you have to change the configuration:

Old:
User: Objectclass=dominoPerson
SMTP-Address: SMTP-Attribute=mail
New:
User: Objectclass=*
SMTP-Address: SMTP-Attribute=mail;cn

If your users have Internet-Email-Aliases in their shortName field in the person document, you have to also add the LDAP-attribute "uid".