540. Objection to substantive jurisdiction of the arbitral tribunal.

An objection that the arbitral tribunal1 lacks substantive jurisdiction2 at the outset of the proceedings must be raised by a party3 not later than the time he takes the first step in the proceedings to contest the merits of any matter in relation to which he challenges the tribunal's jurisdiction4. A party is not precluded from raising such an objection by the fact that he has appointed or participated in the appointment of an arbitrator5. Any objection during the course of the arbitral proceedings that the tribunal is exceeding its substantive jurisdiction must be made as soon as possible