(1) The number of arbitrators and the method of their appointment must be determined before the Secretary-General can act on any appointment proposed by a party.

(2) The parties shall endeavor to agree on any uneven number of arbitrators and the method of their appointment. If the parties do not advise the Secretary-General of an agreement within 45 days after the date of registration, the Tribunal shall consist of three arbitrators, one arbitrator appointed by each party and the third, who shall be the President of the Tribunal, appointed by agreement of the parties.