How to make active Birthdays from Contacts to Calendar?

After exporting or copying Contacts from another .pst file that contains filled Birthdays’ dates, these Birthdays do not appear in Calendar or Outlook Today. How to activate them? Birthdays you write in directly in Contacts appear in other Outlook screens – Calendar or Outlook Today, but exported or copied Birthdays you can see only in your Contact table. Didn’t you meet such problem?