I have a little problem using the Tool Path -> Diffrence.
If I just have two circles and wanna cut the overlapping part it works fine.
Now I have this image where the grey part is an gardient from white to transparent (the background on the layer behind this is black) and the green circle is my "rubber stamp"

What I wanna have is the red-marked part here:

And this is what I get after using Path -> Diffrence

Any ideas how to get the needed result?
Thanks in advance
flappix