I am sorry, but I must be misunderstanding something, because it doesn't seem to work.
What I have done to simulate feathering is the following:
1) Duplicate layer on background.
2) On the new layer:
3) Use rectancle select to select the center of the image (25 pixels or so to the edges)
4) Invert Selection
5) Using the Paintbrush tool to paint the selection with White.
6) Setting layer opacity to about 160.
7) Using Gaussian blur on 3.
It works, but it lacks the gradience from obscure to crisp that feathers should have.