English to Spanish Law/Patents Law (general)

Esta traducción del testamento está resultando ser un verdadero dolor de cabeza para mí.

""I give all my real and personal estate ... unto my trustee upon trust with power to sell, call in and convert same into money and with the monies so produced and with my cash assets to pay all my debts funeral and testamentary expenses, all legacies (if any) given by this Will or any codicil, all duties payable on any legacy or bequest given free of duties and all payments directed to be made out of residue and to **hold the balance then remaining** ("my residuary estate") **upon** the following trusts, namely:..."

He colocado: the balance the remaining = el saldo restante. Tengo problemas para traducir la construcción verbal