Question about Outlook Express

I use my own company's e-mail in Outlook 2011 for Mac.

I noticed the e-mails 1 year old have disappeared from my folders. It matches exactly 1 year before the current date.

I checked with my server provider and by default setup, emails are never deleted from the server.

I use it in IMAP set up as I also use in my iPhone with apple mail. I never had problems using IMAP in 3 devices (phone, webmail and Outlook)

I was forced to delete my Outlook account to avoid loose more e-mails. Now i can only access the webmail to avoid more important emails been deleted. I wanna re-activate my Outlook, but so far still didn't find any solution for my lost mails.

At second I deleted the account from the phone too, and so far no more e-mails has been deleted.

I tried to check any automatic archive set up/rules in my outlook, but so far didn't afind anything. I'm using IMAP default setup.

It's really strange!! I'd like to know if anybody else has encountered same problem and what's the solution.

I recently installed Office for Mac 2011 Home & Business because I wanted to update from Office for Mac 2008. Both are still on my computer.

I have 1 problem and 1 question:

Problem: I don't know how to make Outlook my default email program. My emails are going to my Entourage 2008, not Outlook 2011. I was able to import all my emails from Entourage to Outlook without any problems.

Question: How can I get my Outlook calendar to sync with my calendar on my Mac or my iPhone.