"trustee" aquí tiene el sentido de persona que actúa en interés de otro...

Traducción:

"... es depositario/consignatario/fiduciario de la promesa relativa a las obligaciones del Demandado derivadas de la Póliza o, alternativamente, es depositario... de la promesa del Demandado de indemnizar las pérdidas cubiertas (por la póliza) sufridas por los asegurados"

http://books.google.es/books?id=q3JVfKMoWcIC&pg=PA88&lpg=PA8...

Ver explicación:

"A trust can attach to the benefit of the whole contract or of the whole or part of some particular contractual obligation. In the case of a policy of liability insurance under which the insurer agrees to indemnify both a party to the contract and others, there is no reason in principle or in common sense why the party to the contract should not hold the benefit of the **insurer’s promise to indemnify him on his own behalf and the benefit of the promise to indemnify others respectively upon trust for those others**. **Where the benefit of a contractual promise is held by the promisee as trustee for another**, an action for enforcement of the promise or damages for its breach can be brought by the trustee. In such an action, the trustee can recover, on behalf of the beneficiary, the damages sustained by the beneficiary by reason of breach. If the trustee of the promise declines to institute such proceedings, the beneficiary can bring proceedings against the promisor in his own name, joining the trustee as defendant"

sydney.edu.au/lec/.../Nature%20of%20Trusts.ppt‎

"Persona que actúa en interés de otra sin hacerlo público"

http://lema.rae.es/drae/?val=fiduciario