I am also having a problem getting my friends to show up on the list when you try to create a challenge. I have several friends on my Xbox Friends list that have the achievement but they do not show up. I also linked my wife's account and she also does not show up.
When I follow the link posted above to sign in with a LIVE account, it redirects me to the yourshape dashboard but none of the options are clickable except for login and FAQ (even though in the black navigation bar at the top of the page it shows my uplay username and gives me the option to logout :? ). When I login and go to create a challenge, no friends show up.
This is getting a little frustrating. So can I FR someone who could then create a challenge that includes me?
GT: nfn nifty
uplay user: nfntjy