[NTG-context] \footnote in \placefigure

Dear ConTeXt users, I am using the following piece of code: \placefigure[right]{Zerfall von Pangäa\footnote{\hyphenatedurl{http://www.geologie.uni-frankfurt.de/staff/Homepages/Oschmann/Oschmann/Homepage/P21-Homepage/P21-9-Evolution.html}, zugegriffen am 3. Januar 2010}}{\externalfigure[Zerfall_von_Pangäa][width=70mm]} It works for some figures but for others it doesn't. In the second case neither the footnote nor the number in the subtitle of the picture is shown. Could anyone explain me why this happens and how to fix it? Thanks in advance. Regards, Hannes