removing security-realm attribute in jboss-ejb-client.xml causes failures

The following exception occurs when the security-realm attribute is removed

15:14:17,273 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-7) MSC00001: Failed to start service jboss.deployment.unit."xxi-framework-test-modul
e-deploy-ejb.ear".POST_MODULE: org.jboss.msc.service.StartException in service jboss.deployment.unit."xxi-framework-test-module-deploy-ejb.ear".POST_MODUL
E: JBAS018733: Failed to process phase POST_MODULE of deployment "xxi-framework-test-module-deploy-ejb.ear"
at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:123) [jboss-as-server-7.1.2.Final.jar:7.1.2.Fin
al]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [rt.jar:1.7.0_04]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) [rt.jar:1.7.0_04]
at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_04]
Caused by: java.lang.IllegalArgumentException: Name segment is null for security_realm
at org.jboss.msc.service.ServiceName.of(ServiceName.java:82) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at org.jboss.msc.service.ServiceName.append(ServiceName.java:112) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at org.jboss.as.ejb3.remote.EJBClientCommonConnectionConfig$CallbackHandlerProvider.<init>(EJBClientCommonConnectionConfig.java:114)
at org.jboss.as.ejb3.remote.EJBClientCommonConnectionConfig.setCallbackHandler(EJBClientCommonConnectionConfig.java:86)
at org.jboss.as.ejb3.remote.EJBClientClusterConfig.<init>(EJBClientClusterConfig.java:72)
at org.jboss.as.ejb3.deployment.processors.EJBClientDescriptorMetaDataProcessor.createClientConfiguration(EJBClientDescriptorMetaDataProcessor.jav
a:158)
at org.jboss.as.ejb3.deployment.processors.EJBClientDescriptorMetaDataProcessor.deploy(EJBClientDescriptorMetaDataProcessor.java:89)
at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:116) [jboss-as-server-7.1.2.Final.jar:7.1.2.Fin