(1) The party or parties concerned shall notify the Secretary-Gen- eral of the appointment of each arbitrator and indicate the method of his appointment.

(2) As soon as the Secretary-General has been informed by a party or the Chairman of the appointment of an arbitrator,he shall seek an acceptance from the appointee.

(3) If an arbitrator fails to accept his appointment within 15 days, the Secretary-General shall promptly notify the parties, and if appro- priate the Chairman,and invite them to proceed to the appointment of another arbitrator in accordance with the method followed for the pre- vious appointment.