POST /egroupware/groupdav.php/user01/outbox/ HTTP/1.1
Host: boulder.outdoor-training.de
Content-Type: text/calendar; charset="utf-8"
Authorization: Basic dXNlcjAxOnVzZXIwMQ==
Content-Length: 311

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Example Corp.//CalDAV Client//EN
METHOD:REQUEST
BEGIN:VFREEBUSY
UID:4FD3AD926350
DTSTAMP:20140408T143500Z
DTSTART:20140408T000000Z
DTEND:20140408T230000Z
ORGANIZER:mailto:user.one@outdoor-training.de
ATTENDEE:mailto:user.two@outdoor-training.de
END:VFREEBUSY
END:VCALENDAR
