Bug in SP1 of Microsoft Outlook 2011 for Mac - Service Pack 1?

I am running MS Outlook 2011 for Mac (version 14.2.2 (120421)) on a MacBook Pro with OS X 10.6.8. I only use Outlook for my email.

After installing SP1 for Outlook, all my calendars disappeared from iCal and from my iPhone! I still had them on my iPad which was not yet synchronized, so I added them manually back to iCal, including all my future appointments. Then I synchronized my MacBook with iPad and my iPhone. This deleted my calendar history on the iPad but at least the future appointments were back again. I ensured that a good backup was present on my Time Machine.

A few days later I noticed that all calendars had disappeared again from iCal and from my iPhone! Then I discovered that Outlook had imported the new calendars from iCal and apparently deleted them in Cal, along with the old appointments. I turned on Sync Services to bring them back to iCal. That worked: the calendars were copied back to iCal.

When I tried to synchronize my data with my iPhone, I got the following error message: "iTunes could not sync information to the iPhone (...) because another sync client is already running" .

I then turned off Sync Services in MS Outlook 2011 for Mac and restarted my MacBook. I could synchronize my data with my iPhone again, but... Outlook had again deleted my calendars from iCal!

Restoring my backup did not solve the problem. I can either synchronize while Outlook deletes my calendars or keep my calendars and not synchronize.

How can I stop Outlook from deleting my iCal calendars?