Cannot inject ValidatorFactory

In a singleton session bean I have this declaration:
@Singleton
@Lock(READ)
public class ValidationService implements Serializable {
@Resource
private ValidatorFactory validatorFactory;

When deploying my EAR in JBoss 6.0.0.M5, I get this stacktrace:

09:39:28,821 ERROR [org.jboss.kernel.plugins.dependency.AbstractKernelController] Error installing to Real: name=vfs:///C:/Users/Public/Documents/eclipse-workspace-swe2/.metadata/.plugins/org.jboss.ide.eclipse.as.core/JBoss_6.0_Runtime_Server1285426262124/deploy/hska.ear state=PreReal mode=Manual requiredState=Real: org.jboss.deployers.spi.DeploymentException: Error deploying: org.jboss.metadata.ejb.jboss.JBossEnterpriseBeanMetaData.ValidationService
at org.jboss.deployers.spi.DeploymentException.rethrowAsDeploymentException(DeploymentException.java:49) [:2.2.0.Alpha7]
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployerWithInput.deploy(AbstractRealDeployerWithInput.java:142) [:2.2.0.Alpha7]
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployerWithInput.internalDeploy(AbstractRealDeployerWithInput.java:102) [:2.2.0.Alpha7]
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployer.deploy(AbstractRealDeployer.java:55) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.deployers.DeployerWrapper.deploy(DeployerWrapper.java:179) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.deployers.DeployersImpl.doDeploy(DeployersImpl.java:1832) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1550) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1571) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.deployers.DeployersImpl.doInstallParentFirst(DeployersImpl.java:1603) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.deployers.DeployersImpl.install(DeployersImpl.java:1491) [:2.2.0.Alpha7]
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:379) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:2044) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:1083) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.executeOrIncrementStateDirectly(AbstractController.java:1322) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1246) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1139) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:939) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:654) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.deployers.plugins.deployers.DeployersImpl.change(DeployersImpl.java:1983) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.deployers.DeployersImpl.process(DeployersImpl.java:1076) [:2.2.0.Alpha7]
at org.jboss.deployers.plugins.main.MainDeployerImpl.process(MainDeployerImpl.java:679) [:2.2.0.Alpha7]
at org.jboss.system.server.profileservice.deployers.MainDeployerPlugin.process(MainDeployerPlugin.java:106) [:6.0.0.20100911-M5]
at org.jboss.profileservice.dependency.ProfileControllerContext$DelegateDeployer.process(ProfileControllerContext.java:130) [:0.1.0.Alpha1]
at org.jboss.profileservice.dependency.ProfileDeployAction.deploy(ProfileDeployAction.java:148) [:0.1.0.Alpha1]
at org.jboss.profileservice.dependency.ProfileDeployAction.installActionInternal(ProfileDeployAction.java:94) [:0.1.0.Alpha1]
at org.jboss.kernel.plugins.dependency.InstallsAwareAction.installAction(InstallsAwareAction.java:54) [jboss-kernel.jar:2.2.0.Alpha10]
at org.jboss.kernel.plugins.dependency.InstallsAwareAction.installAction(InstallsAwareAction.java:42) [jboss-kernel.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.action.SimpleControllerContextAction.simpleInstallAction(SimpleControllerContextAction.java:62) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.action.AccessControllerContextAction.install(AccessControllerContextAction.java:71) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractControllerContextActions.install(AbstractControllerContextActions.java:51) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractControllerContext.install(AbstractControllerContext.java:379) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.install(AbstractController.java:2044) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.incrementState(AbstractController.java:1083) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.executeOrIncrementStateDirectly(AbstractController.java:1322) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1246) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.resolveContexts(AbstractController.java:1139) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:939) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.dependency.plugins.AbstractController.change(AbstractController.java:654) [jboss-dependency.jar:2.2.0.Alpha10]
at org.jboss.profileservice.dependency.ProfileServiceController.activate(ProfileServiceController.java:188) [:0.1.0.Alpha1]
at org.jboss.profileservice.AbstractProfileService.activateProfile(AbstractProfileService.java:170) [:0.1.0.Alpha1]
at org.jboss.system.tools.ProfileServiceToolsFacade.addURI(ProfileServiceToolsFacade.java:217) [:6.0.0.20100911-M5]
at org.jboss.system.tools.LegacyDeploymentScannerAdapter.addURL(LegacyDeploymentScannerAdapter.java:131) [:6.0.0.20100911-M5]
at org.jboss.system.tools.DeploymentScanner.addURL(DeploymentScanner.java:91) [:6.0.0.20100911-M5]
at org.jboss.system.tools.DeploymentScanner.addURL(DeploymentScanner.java:83) [:6.0.0.20100911-M5]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_21]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_21]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_21]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_21]
at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:157) [:6.0.0.Beta5]
at org.jboss.mx.server.Invocation.dispatch(Invocation.java:96) [:6.0.0.Beta5]
at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) [:6.0.0.Beta5]
at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:271) [:6.0.0.Beta5]
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:670) [:6.0.0.Beta5]
at org.jboss.system.server.jmx.MBeanServerWrapper.invoke(MBeanServerWrapper.java:138) [:6.0.0.20100911-M5 (Build SVNTag:JBoss_6.0.0.20100911-M5 date: 20100922)]
at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1427) [:1.6.0_21]
at javax.management.remote.rmi.RMIConnectionImpl.access$200(RMIConnectionImpl.java:72) [:1.6.0_21]
at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1265) [:1.6.0_21]
at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1360) [:1.6.0_21]
at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:788) [:1.6.0_21]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_21]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_21]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_21]
at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_21]
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:305) [:1.6.0_21]
at sun.rmi.transport.Transport$1.run(Transport.java:159) [:1.6.0_21]
at java.security.AccessController.doPrivileged(Native Method) [:1.6.0_21]
at sun.rmi.transport.Transport.serviceCall(Transport.java:155) [:1.6.0_21]
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535) [:1.6.0_21]
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790) [:1.6.0_21]
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649) [:1.6.0_21]
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [:1.6.0_21]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [:1.6.0_21]
at java.lang.Thread.run(Thread.java:619) [:1.6.0_21]
Caused by: java.lang.RuntimeException: mapped-name is required for de.hska.util.ValidationService/validatorFactory of deployment ValidationService
at org.jboss.injection.ResourceHandler.loadXmlResourceEnvRefs(ResourceHandler.java:240) [:1.5.1]
at org.jboss.injection.ResourceHandler.loadXml(ResourceHandler.java:280) [:1.5.1]
at org.jboss.ejb3.EJBContainer.processMetadata(EJBContainer.java:678) [:1.5.1]
at org.jboss.ejb3.singleton.deployer.SingletonContainerDeployer.deploy(SingletonContainerDeployer.java:215) [:1.0.0-alpha-12]
at org.jboss.ejb3.singleton.deployer.SingletonContainerDeployer.deploy(SingletonContainerDeployer.java:85) [:1.0.0-alpha-12]
at org.jboss.deployers.spi.deployer.helpers.AbstractRealDeployerWithInput.deploy(AbstractRealDeployerWithInput.java:125) [:2.2.0.Alpha7]
... 71 more