Something

        public static Int64 GetTimeStamp(ISession session)
        {
            var query = from account in session.Query<BitCoinEscrowAccount>()
                        orderby account.TimeStamp descending
                        select account;

            var row = query.FirstOrDefault();

            if (row == null)
                return 1;
            else
                return row.TimeStamp + 1;

        }