i tried with hibernate 4.0 CR7 . I also have the same issue.
new MetadataSources(new ServiceRegistryBuilder()
.buildServiceRegistry())
.buildMetadata().
buildSessionFactory()
Caused by: org.xml.sax.SAXParseException; lineNumber: 5; columnNumber: 26;
cvc-elt.1: Cannot find the declaration of element 'hibernate-configuration'.

On the wbesite , it is clearly & bodly saying that work is on process. Not to use this ...

But When i use config.buildSessionFactory(); i get following
session = config.buildSessionFactory().tenantIdentifier("XXX").openSession();

i get
java.lang.NullPointerException
at org.hibernate.engine.jdbc.internal.JdbcServicesImpl$MultiTenantConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcServicesImpl.java:245)
at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:113)



but same code works with 3.6 ...i am stuck .