A power of appointment is exercised only: (1) if the instrument exercising the power is valid under applicable law; (2) if the terms of the instrument exercising the power: (A) manifest the powerholder's intent to exercise the power; and (B) subject to section 30-4614, satisfy the requirements of exercise, if any, imposed by the donor; and (3) to the extent the appointment is a permissible exercise of the power.