An entity with a lazy property cannot be saved in new session

An entity with a lazy property cannot be loaded from one session and saved from another.
This is because the entity is a proxy object, but it is not an INHibernateProxy. Therefore, when it is attached to the new session NHibernate reads it's type as the Proxy type and it can't find the appropriate persister.
The attached patch fixes this by using NHibernateProxyHelpter.GuessClass instead of just running GetType on the entity.

I have only tested this with the Castle ByteCode, it may not be an issue for the others.