using (ISession s = NHibernateSessionManager.Instance.GetSession())
{


      var implementor = s.GetSessionImplementation();
      var driver = implementor.Factory.ConnectionProvider.Driver;

      SqlType[] param = new SqlType[3]
      {
          new SqlType(DbType.String),
          new SqlType(DbType.Int32),
          new SqlType(DbType.String)};

      IDbCommand cmd = driver.GenerateCommand(CommandType.StoredProcedure, new SqlString("test.proc1"), param);

      OracleParameter p1 = ((OracleCommand)cmd).Parameters[0];
      OracleParameter p2 = ((OracleCommand)cmd).Parameters[1];
      OracleParameter p3 = ((OracleCommand)cmd).Parameters[2];
      
      cmd.ExecuteNonQuery();
}

ISession s = NHibernateSessionManager.Instance.GetSession();
            IQuery q = s.CreateSQLQuery("begin test.proc1(:a, :b, :c); end;")
                .SetString("a", "asd")
                .SetInt32("b", 23)
                .SetString("c","");
            q.ExecuteUpdate();