Remove a roud from crssing and setting new.

Hi
I have a problem on a roundabout to modify the whole crossing. It is compleatly wrong. From south west i have to splitt two incoming roads and on north east modify the exit.
Now I need to know, how to remove a road from the roundabout and set it new correctly
See:
http://www.openstreetmap.org/?lat=46.727121&lon=7.137423&zoom=19
In center of village

I did send you an answer on your openstreetmap account. Pls have a look.