Problems with images edited with photoshop

Hi, can anyone help with an issue that has just started occuring. When I use the edit with photoshop command - I am able to make the desired adjustments I want in CS5 and save the image back to Aperture but now it won't update the image - I end up with 2 images - the RAW and the PS image that are identical except when I go to browser mode - then I can see the difference in them. If I quit A3 and re-open I can see the edited version but as soon as I go to edit another image it reverts to the same problem - in viewer mode the image is the pre-edited version. Any clues please?