vCAC 6.0 Identity Appliance

I am doing the POC for vCAC 6.0. Question here is when i have already SSO deployed do we really need Identity Appliance? I know we can use SSO instead of IA but after the implementation i was facing System Exception error when i try to create tenants and was not able to login with the domain users

Error message:

2014-05-14 14:08:49,362 [tomcat-http--8] [authentication] ERROR com.vmware.vcac.platform.service.rest.resolver.ApplicationExceptionHandler.handleUnexpectedException:86

0 - General failure.

com.vmware.vcac.platform.service.SSOException: General failure.

        at com.vmware.vcac.authentication.service.sso.impl.TenantManagementImpl.createTenant(TenantManagementImpl.java:93)

        at com.vmware.vcac.authentication.service.impl.TenantServiceImpl.save(TenantServiceImpl.java:99)

        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

        at java.lang.reflect.Method.invoke(Unknown Source)

        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)

        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)

        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)

        at org.springframework.aop.framework.adapter.AfterReturningAdviceInterceptor.invoke(AfterReturningAdviceInterceptor.java:51)

        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161)

        at org.springframework.cache.interceptor.CacheInterceptor$1.invoke(CacheInterceptor.java:58)

        at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:214)

        at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:66)

I followed "VMware KB: vCloud Automation Center 6.0.x tenants become inaccessible and identity stores disappear " but no luck. Can anyone tell me do we really need IA eventhough when we have SSO in place?