ejb-jar.xml does not understand tag <concurrent-method> for singleton session type

ERROR [org.jboss.msc.service.fail] (MSC service thread 1-7) MSC00001: Failed to start service jboss.deployment.unit."ejb3-singleton-bean-example.jar".POST_MODULE: org.jboss.msc.service.StartException in service jboss.deployment.unit."ejb3-singleton-bean-example.jar".POST_MODULE: Failed to process phase POST_MODULE of deployment "ejb3-singleton-bean-example.jar"
	at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:119) [jboss-as-server-7.1.0.Final-SNAPSHOT.jar:7.1.0.Final-SNAPSHOT]
	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$Worker.runTask(ThreadPoolExecutor.java:886) [rt.jar:1.6.0_23]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [rt.jar:1.6.0_23]
	at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_23]
Caused by: org.jboss.as.server.deployment.DeploymentUnitProcessingException: JBAS014402: Could not merge data for ReadOnlySingletonBeanDescriptor
	at org.jboss.as.ejb3.deployment.processors.merging.AbstractMergingProcessor.deploy(AbstractMergingProcessor.java:75)
	at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:113) [jboss-as-server-7.1.0.Final-SNAPSHOT.jar:7.1.0.Final-SNAPSHOT]
	... 5 more
Caused by: java.lang.NullPointerException
	at org.jboss.as.ejb3.deployment.processors.merging.EjbConcurrencyMergingProcessor.resolveMethod(EjbConcurrencyMergingProcessor.java:134)
	at org.jboss.as.ejb3.deployment.processors.merging.EjbConcurrencyMergingProcessor.handleDeploymentDescriptor(EjbConcurrencyMergingProcessor.java:111)
	at org.jboss.as.ejb3.deployment.processors.merging.EjbConcurrencyMergingProcessor.handleDeploymentDescriptor(EjbConcurrencyMergingProcessor.java:53)
	at org.jboss.as.ejb3.deployment.processors.merging.AbstractMergingProcessor.processComponentConfig(AbstractMergingProcessor.java:93)
	at org.jboss.as.ejb3.deployment.processors.merging.AbstractMergingProcessor.deploy(AbstractMergingProcessor.java:73)
	... 6 more