Mode of executing testamentary appointment

(1) No appointment made by will in exercise of any power shall be valid unless it is executed in manner hereinbefore (2) Every will executed in manner hereinbefore required shall, so far as respects the execution and attestation thereof, be a valid execution of a power of appointment by will, notwithstanding it has been expressly required that a will made in exercise of such power shall be executed with some additional or other form of execution or solemnity.