DateObject creation fails if month name is in incorrect case

If anyone is curious, as a workaround for this issue I created the following function and added it to the date_popup element's '#element_validate' attribute. It gets called before date_popup_validate() so it can fix the case if necessary.

function my_module_date_popup_element_validation_helper($element, &$form_state) {
  // Get the date value from the passed-in element.
  $date = $element['#value']['date'];

  // If the value isn't in the proper format (d-M-Y), we don't need to do
  // anything here since date_popup_validate() will handle it.
  if (empty($date) || !preg_match('/^\d{1,2}\-[a-zA-Z]{3}\-\d{4}$/', $date)) {
    return;
  }

  // Split the date into day, month, and year.
  list($day, $month, $year) = explode('-', $date);

  // If the month name is capitalized properly, we can exit this function.
  if (preg_match('/^[A-Z][a-z]{2}$/', $month)) {
    return;
  }

  // Otherwise, we need to ensure than the first letter is in uppercase while
  // the remaining two letters are in lowercase. Note that the date may still be
  // invalid, but date_popup_validate() will handle proper date validation.
  $month = drupal_ucfirst(drupal_strtolower($month));

  // Put the date back together with the modified month.
  $date = $day . '-' . $month . '-' . $year;

  // Set the actual value that will be used in date_popup_validate().
  form_set_value($element, array('date' => $date, 'time' => ''), $form_state);

  // Setting this will cause the updated value to be displayed when the form
  // is rendered after being submitted without any errors.
  $form_state['input'][$element['#name']]['date'] = $date;

  // Setting this will cause the updated value to be displayed when the form
  // is rendered after being submitted with errors.
  $form_state['complete form'][$element['#name']]['date']['#value'] = $date;

  // Setting these doesn't seem to have any effect, but for the sake of
  // completeness, we might as well overwrite the old value everywhere.
  $form_state['complete form'][$element['#name']]['#value']['date'] = $date;
  $form_state['complete form'][$element['#name']]['date']['#default_value'] = $date;
}