Property Substitution not working while using TCP for cluster communication in EAP 6

Issue

• Property Substitution not working while using TCP for cluster communication :

<stack name="tcp">
    <transport type="TCP" socket-binding="jgroups-tcp"/>
    <protocol type="TCPPING">
        <property name="initial_hosts">
            ${test.tcpping.ha.init.members:10.1.2.3[7600],10.1.2.3[7601]}
        </property>
    ...
</stack>

Above stack is from "standalone-full-ha.xml", we get below exception while starting the server:

ERROR [org.jboss.msc.service.fail] (pool-14-thread-1) MSC000001: Failed to start service jboss.jgroups.channel.web: org.jboss.msc.service.StartException in service jboss.jgroups.channel.web: java.lang.Exception: String value could not be converted for method initial_hosts in TCPPING with default value ${test.tcpping.ha.init.members:10.1.2.3[7600],10.1.2.3[7601]}.Exception is java.lang.Exception: Conversion of initial_hosts in TCPPING with original property value ${test.tcpping.ha.init.members:10.1.2.3[7600],10.1.2.3[7601]} failed
...