ti cito l'ultimo messaggio del product manager di NHibernate alla mailing list degli sviluppatori :

"I have updated JIRA to reflect the current roadmap to 1.2.0. I'm
currently working on stored procedures and as soon as I finish them and
a few other easy issues, I will release 1.2.0.Beta1. After that, I will
implement several other less important features and make a Beta2 release
which will also probably become a release candidate and later a release
if no critical bugs are found."

per il momento secondo me devi ottenere la connectionstring dalla sessione di NHibernate ed utilizzare ADO.NET