When a donee is authorized to appoint to himself all or part of the property covered by any power of appointment, a creditor of the donee may subject to his claim all property which the donee could then appoint to himself only to the extent that other property available for the payment of his claim is insufficient for such payment. When a donee has exercised such a general power by deed, the law relating to fraudulent conveyances shall apply as if the property transferred to the appointee had been owned by the donee. When a donee has exercised such a power by will in favor of either a taker without value or a creditor, a creditor of the donee or of his estate may subject such property to the payment of his claim only to the extent that other property available for the payment of the claim is insufficient for such payment.