We found that JBoss was loading its own email utility. By removing the following code from the jboss standalone.xml file, we were able to use the Lucee mail integration.
<extension module="org.jboss.as.mail"/>
<subsystem xmlns="urn:jboss:domain:mail:3.0">
<mail-session name="default" jndi-name="java:jboss/mail/Default">
<smtp-server outbound-socket-binding-ref="mail-smtp"/>
</mail-session>
</subsystem>
<outbound-socket-binding name="mail-smtp">
<remote-destination host="localhost" port="25"/>
</outbound-socket-binding>