Hi Cyrus I thought you had replied to me personally instead of to the list. Therefore just to keep the mailinglist up-to-date, the problem was caused by me using the direct calendar url instead of the principals url. iCal requires the principals url to be used, while other clients such as Sunbird/Lightning require the direct calendar url. I now have the system set up and working. Are there any updates on using an LDAP server instead of Open Directory to solve the issues with Delegates and the Address Panel. In the archives I found that a special iCal schema was required which in turn depended on Apple specific libraries not available outside the Darwin platform. I'm interested in hearing if anyone made any progress on that? Best regards tom