How do I increase the timeout in NHibernate Linq To Sql?

Not the Connection Timeout but the ado command timeout.

using (ISession session = NHibernateHelper.OpenSession(NHibernateHelper.Databases.CarrierCDR))
  using (session.BeginTransaction(IsolationLevel.ReadUncommitted))
  {
   lCdrs = (from verizon in session.Linq<Domain.Verizon>()
             where verizon.Research == true
             && verizon.ReferenceTable == null
             orderby verizon.CallBillingDate descending 
              select verizon).ToList();
}