After the BL Update the Button "Radar activate" in the Profil disappeared.
If you want to put someone in the list, you must klick on his profile and then again on his name below.
On the second side the button works fine.
Example:
no button:
http://battlelog.battlefield.com/bf3/en/user/blaiskiller/
button:
http://battlelog.battlefield.com/bf3/en/soldier/blaiskiller/stats/366158417/