The way externally edited images are handled in Aperture 2 is somewhat different than in past versions. In prior versions, the TIFF or PSD file created by Aperture for external editing was always stored as a managed image in the Aperture library, whether the source image was managed or referenced. In Aperture 2, externally edited images are automatically stored at the same location as the original. After you have edited the image externally, you can choose File > Relocate Master to move the image to any location you like.