Everyone the simplest way is to do this:

In Calendars

1. Settings
2. Edit Calendars
3. Click "Birthdays"
4. Delete (wont actually delete the data)

Press Back

5. "New"
6. Select "Birthdays Smart Calendar"
7. Next.
8. Finish.

Now ALL your entries should show in the calendar widget .No need to manually edit and confirm each contacts birthday.