(1) The parties are to be accorded equal treatment. Each party is to be given an effective and fair legal hearing.
(2) Attorneys may not be precluded from acting as attorneys-in-fact.
(3) In all other cases, the parties are free to establish rules for the procedure themselves or to refer to an existing set of arbitration rules, in each case subject to the mandatory provisions of the present Book.
(4) Absent an agreement by the parties, and in the event the present Book has remained silent in this regard, the arbitral tribunal lays down the rules of procedure at its sole discretion. The arbitral tribunal is entitled to decide on the admissibility of taking evidence, to take evidence and to freely assess the evidence.