EAP server shows as unavailable if instance name is a variable in standalone.xml in JBoss ON

Issue

• EAP server still shows as unavailable in JBoss ON after entering correct credentials
• Below message in agent.log

2016-04-05 09:33:34,863 INFO  [ResourceContainer.invoker.availCheck.daemon-78] (rhq.modules.plugins.jbossas7.ASConnection)- {
  "outcome" : "success",
  "result" : {
    "EXPRESSION_VALUE" : "${jboss.instance.name}"
  }
}