Open the old SU file with the camera position you want / need, save the model under a different file name (so as to not mess up the old one you're keeping for record), save the camera position as a scene, delete unwanted scenes. Use PageExIm available from Smustard to export the scene. Open updated SU model, use PageExIm to import the scene into your new model.
That should do the trick, make sure you don't have conflicting scene names.