All the domains listed in the Global Domain document are seen as Internal hosts, they do not have relay restrictions applied, and are able to relay messages.
Make sure you re-start the server after adding this param.
Use this setting to determine whether all hosts should be subject to the anti-spam controls specified for the server.
Valid Values are:
0 - Exempts internal hosts from anti-spam controls.
1 - Internal hosts included for anti-spam controls.
This setting can be used when a firewall with two network interface (NIC) cards is used to connect over a transparent connection to the Domino R5 server. The connecting IP address is the internal IP address of the firewall; therefore, the relay is allowed through the Domino R5 server.
This setting is described in further detail in the document titled "Domino R5 SMTP Relay Controls Do not Restrict Internal Hosts" (#1091028).