There is missing chapter (in Administration and Configuration Guide) describing alternative way of configuring server discovery using JGroups in messaging subsystem. More info about it can be found in community documentation [1].

Example of configuration for EAP 6.2 for broadcast group and discovery group:
                 <broadcast-groups>
                    <broadcast-group name="bg-group1">
                        <jgroups-stack>udp</jgroups-stack>
                        <jgroups-channel>udp</jgroups-channel>
                        <broadcast-period>2000</broadcast-period>
                        <connector-ref>
                            netty
                        </connector-ref>
                    </broadcast-group>
                </broadcast-groups>

                <discovery-groups>
                    <discovery-group name="dg-group1">
                        <jgroups-stack>udp</jgroups-stack>
                        <jgroups-channel>udp</jgroups-channel>
                        <refresh-timeout>10000</refresh-timeout>
                    </discovery-group>
                </discovery-groups>


[1] http://docs.jboss.org/hornetq/2.4.0.beta1/docs/user-manual/html_single/index.html#d0e10420