The power of an attorney-in-fact to bind the fidelity and surety insurer as surety within the authority conferred by a power of attorney recorded pursuant to subsection A of § 38.2-2416, shall, unless the power of attorney is otherwise limited, continue for the agency until the expiration of the power of attorney or until the power is revoked by the insurer’s sealed written instrument duly acknowledged for recordation and admitted to record in the county or corporation in which the power of attorney is recorded.