--- /tmp/export_execute.php	2011-12-15 13:15:16.930923725 +0200
+++ export_execute.php	2011-12-15 13:01:16.522925168 +0200
@@ -119,6 +119,8 @@
 
 $ical = new iCalendar;
 $ical->add_property('method', 'PUBLISH');
+$ical->add_property('calscale', 'GREGORIAN');
+$ical->add_property('X-LOTUS-CHARSET', 'UTF-8');
 foreach($events as $event) {
    if (!empty($event->modulename)) {
         $cm = get_coursemodule_from_instance($event->modulename, $event->instance);
@@ -167,7 +169,7 @@
 header('Accept-Ranges: none'); // Comment out if PDFs do not work...
 header('Content-disposition: attachment; filename='.$filename);
 header('Content-length: '.strlen($serialized));
-header('Content-type: text/calendar');
+header('Content-type: text/calendar; charset=UTF-8');
 
 echo $serialized;