However, that said and done I always thought that the USAF/Americans only knew it as the B-57, as that is how they nearly always refer to it. Thought the ‘Canberra’ thing was just a Martin show to keep E.E.co. happy.

The official list of designations, DoD Document 4120.15-L ‘Model Designation of Military Aerospace Vehicles’, lists B-57 variants as Canberra.

http://www.dtic.mil/whs/directives/corres/pdf/412015l.pdf