Form validation: Callback not changing the input value

[eluser]TheFuzzy0ne[/eluser]
Oh, and another thing. You're validating the day against the current year. Surely that's not right?

Code:

if (0 > $day || $day > (int)date('Y')) {
    $this->validation->set_message('validate_birthday', 'Invalid year in birthdate.');
    return false;
}