Where Member States designate the customer for investment gold as the person liable for payment of VAT pursuant to Article 198(1) or if, in the case of gold material, semi-manufactured products, or investment gold as defined in Article 344(1), they exercise the option provided for in Article 198(2) of designating the customer as the person liable for payment of VAT, they shall take the measures necessary to ensure that he complies with the payment obligations set out in this Section.