Valdes, along with the future Secretary of Foreign Affairs Raul Manglapus, at the time a reporter for the Philippines Free Press, were the only two Filipinos accredited to join MacArthur during the signing of the Instrument of Surrender on board the USS Missouri in Tokyo Bay on 2 September 1945. Valdes received one of 20 original facsimiles of the Instrument of Surrender, being one of eight personal guests of MacArthur, and his document is currently owned and curated by The International Museum of World War II in Natick, Massachusetts.