NHibernate with TransactionScope

I have been using nHibernate 2.1 for awhile, and after a few production issues and trying quite a few variations, we have settled on the following method, as per Avoiding Leaking Connections With NHibernate And TransactionScope:

        using (var scope = new TransactionScope(TransactionScopeOption.Required))
        {
            using (var session = sessionFactory.OpenSession())
            using (var transaction = session.BeginTransaction())
            {
                // do what you need to do with the session
                transaction.Commit();
            }
            scope.Complete();
        }

As we are using MSMQ and WCF so we had to use the ambient transaction.

We found that not using session.BeginTransaction() caused a connection leak.
We also found that re-using a session after committing a transaction caused a race condition (nHibernate is not thread safe and DTSC Commits/Rollbacks occur on a background thread).