iphoto with editing in Picasa

I am unable to save photo edited in Picasa back to an album in iphoto. I select a photo in an iphoto album and click the edit button and ask to edit the photo in Picasa. It immediatley creates a duplicate in the iphoto album, when I then go to the Picasa edit screen it again asks me to make a duplicate image. After editing this image in Picasa I click "done" and then "save". The edited image is saved in Picasa but I cannot find a way to get the edited image back into my iphoto album. Occasionally I will get a shadow image of the photo in the Picasa edit screen and when I edit that screen the edited copy goes back to iphoto, but I cannot find any consistent way of obtaining that shadow image.