Start the game, then watch the Harajuku scouting video sequence (choice in the middle). On the next screen, after all text is displayed, press and hold L1; another text screen will appear, keep holding L1, and press Triangle after all text is displayed; the Birthday Input Screen will appear immediately after pressing the button. This will allow you to see a secret video sequence of Yumie giving you a birthday present on the day you input; however, make sure not to choose February 10th as your birthday, as that video sequence will override Yumie's own Birthday Event.