Windows Live adding birthdays and syncing

When I go to the drop down box in WLM for "birthday calendar", the add  event is greyed out. When I add the b day to the contact info in WLM, it does not add to the calendar. When I add the b day to the outlook.com contact it does not add to the calendar. However if I add the bday suing the drop down to the outlook.com calendar it does add to that calendar and does then sync to the WLM calendar.