I'm using Mac OS X Lion 10.7.5 with Outlook 2011 and this was working for approx 6 months so please do not tell me it is not possible to sync Calendars with iCal. My contacts were also syncing in perfect harmony.

A couple of weeks ago this stopped working. I'm not sure why, I don't think I updated. iTunes 11 was syncing the data between Outlook and iCal. There were no duplicates; it was beautiful.

I have conducted a huge amount of time and effort; at least 72 straight solid hours now. I was wrongly informed that the problem was iTunes being 11 no longer supporting syncing. However it was working for a considerable amoutn of time. 

Currently iTunes is not the problem as the syncing between iCal and Outlook 2011 is constantly syncing. It now is duplicating all day events and it does not finish; it runs imminently. I've had to turn off sync services at the moment.

What I've tried:

1. I've trashed all my preferences within Library > Preferences.;
2. I've deleted Outlook 2011 and reinstalled several times, trying to use an older version (service pack 1 - 14.1.0).
3. I tried creating a new User Identity as I thought my calendars may be corrupted so I thought I'd be able to delete my duplicates in iCal with a script (iCal Dupe Deleter works well) then syncing from iCal back to Outlook. This resulted in another imminent sync. 
4. You cannot rebuild the Microsoft User Data from where I was using a more updated User Data e.g. 14.4.9 seems to be the oldest version I can run with my User Data. I tried rebuilding my User Data by copying the Header Rows of a new User Identity database which was a suggested workaround - it did not work;

What can I do to get this to work? It is possible to get this to work and it should. I've also been chatting about my endeavours in this link too.

Grateful of any guidance.