English to French Bus/Financial Law (general) Terminologie juridique / crédit immobilier

Bonjour
Comment traduire "fully and properly executed or authenticated"...je trouve plrs solutions mais difficile de trouver des adverbes applicables à 'executed et authenticated 'pleinement et dûment...????. Je ne suis d'ailleurs pas certaines que l'on puisse utiliser "exécuter"...
merci pr votre aide.

Origination by a Dealer.
2. Each Receivable has been originated in the USA by a Dealer for the retail sale of a Financed Vehicle in the ordinary course of such Dealer’s business, has been ***fully and properly executed or authenticated***** by the parties thereto, (...) and has been validly assigned by such Dealer to the Originator.