Outlook and the orphaned shared private appointment

Had a bit of an issue this morning when 'someone' accidentally put a private appointment into a shared Outlook Calender thinking it was their own.

Once the (recurring!) appointment was saved no users of the calender were able to read, modify or delete the item - even the 'person' who put the appointment in there. How to fix?

I created a new Outlook profile for the user who owns the mailbox and then opened with Outlook 2007. Straight into the Calender and removed the appointment for this user, great, problem solved, or so i thought. Went back and checked the shared Calender with my profile and the appointment was still there, disappointing, still unable to edit it too.

After a fair bit of playing (cached mode, reopening the mailbox, creating duplicate appointments) I found a way to remove the item.

Open the mailbox through Outlook and salvage the appointment from the deleted items folder. Once it is back in the Calender, remove the "Private" status and then delete. This seemed to do the job but there was a fair bit of hassle, not sure if this is a 'feature' of Outlook and Exchange or whether it is meant to behave like that!

For the record we are running Exchange 2003 and the Outlook client was 2007.