ovirt-engine-backend: Creation of Shared Floating Direct Lun HardDisk causes NullPointerException. 

scenario:
**********
- From 'Disks' Tab --> Add External (Direct Lun) + Check the 'Is Shareable' check-box.

Results:
*********
Action Failed with NullPointerException.

Note:
It happens only when the 'Is Shareable' checked.

engine.log :
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2012-08-22 15:28:16,393 INFO  [org.ovirt.engine.core.bll.AddDiskCommand] (ajp-/127.0.0.1:8009-2) Lock Acquired to object EngineLock [exclusiveLocks= key: aa6953d6-ecd9-4a
92-97c1-b5e7431dd168 value: VM_DISK_BOOT
, sharedLocks= key: aa6953d6-ecd9-4a92-97c1-b5e7431dd168 value: VM
]
2012-08-22 15:28:16,398 ERROR [org.ovirt.engine.core.bll.AddDiskCommand] (ajp-/127.0.0.1:8009-2) Error during CanDoActionFailure.: java.lang.NullPointerException
        at org.ovirt.engine.core.bll.AddDiskCommand.canDoAction(AddDiskCommand.java:94) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.CommandBase.InternalCanDoAction(CommandBase.java:496) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.CommandBase.CanDoActionOnly(CommandBase.java:251) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.MultipleActionsRunner.Execute(MultipleActionsRunner.java:77) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.Backend.runMultipleActionsImpl(Backend.java:439) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.Backend.runMultipleActionsImpl(Backend.java:453) [engine-bll.jar:]
        at org.ovirt.engine.core.bll.Backend.RunMultipleActions(Backend.java:414) [engine-bll.jar:]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_03-icedtea]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [rt.jar:1.7.0_03-icedtea]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_03-icedtea]
        at java.lang.reflect.Method.invoke(Method.java:601) [rt.jar:1.7.0_03-icedtea]
        at org.jboss.as.ee.component.ManagedReferenceMethodInterceptorFactory$ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptorFactory.java:72) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:374) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.ovirt.engine.core.utils.ThreadLocalSessionCleanerInterceptor.injectWebContextToThreadLocal(ThreadLocalSessionCleanerInterceptor.java:11) [engine-utils.jar:]
        at sun.reflect.GeneratedMethodAccessor7.invoke(Unknown Source) [:1.7.0_03-icedtea]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.7.0_03-icedtea]
        at java.lang.reflect.Method.invoke(Method.java:601) [rt.jar:1.7.0_03-icedtea]
        at org.jboss.as.ee.component.ManagedReferenceLifecycleMethodInterceptorFactory$ManagedReferenceLifecycleMethodInterceptor.processInvocation(ManagedReferenceLifecycleMethodInterceptorFactory.java:123) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.invocation.WeavedInterceptor.processInvocation(WeavedInterceptor.java:53) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:36) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:53) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ejb3.component.singleton.SingletonComponentInstanceAssociationInterceptor.processInvocation(SingletonComponentInstanceAssociationInterceptor.java:53) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInNoTx(CMTTxInterceptor.java:210) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.supports(CMTTxInterceptor.java:362) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:193) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:42) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:59) [jboss-as-ejb3.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ee.component.TCCLInterceptor.processInvocation(TCCLInterceptor.java:45) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:165) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.as.ee.component.ViewDescription$1.processInvocation(ViewDescription.java:176) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:288) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) [jboss-invocation.jar:1.1.1.Final-redhat-1]
        at org.jboss.as.ee.component.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:72) [jboss-as-ee.jar:7.1.2.Final-redhat-1]
        at org.ovirt.engine.core.common.interfaces.BackendLocal$$$view8.RunMultipleActions(Unknown Source) [engine-common.jar:]
        at org.ovirt.engine.ui.frontend.server.gwt.GenericApiGWTServiceImpl.RunMultipleActions(GenericApiGWTServiceImpl.java:102)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.7.0_03-icedtea]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [rt.jar:1.7.0_03-icedtea]