Hi Robert,
I am not really sure if this works but you can try to change the [dms-service]/standalone/configuration/standalone-full-ha.xml. There is a section like this:
<subsystem xmlns="urn:jboss:domain:mail:2.0">
<mail-session name="default" jndi-name="java:jboss/mail/Default">
<smtp-server outbound-socket-binding-ref="mail-smtp"/>
</mail-session>
</subsystem>
and
<outbound-socket-binding name="mail-smtp">
<remote-destination host="localhost" port="25"/>
</outbound-socket-binding>
I think that the host (and other properties) will be overwritten by the cluster configuration properties but not the port. So the default is Port 25. The attribute ssl="true" on smpt-server could be interessting and the port 465 in socket-binding.
This is also interessting to read: http://www.mastertheboss.com/jboss-server/jboss-configuration/jboss-mail-service-configuration
But I have not tried out so far. So may be we have some tasks to do... It is possible that we ignore the jboss configuration properties while sending the mails.
best regards