flag specific emails using the follow-up function

Hi Experts,

When reviewing my incoming emails in Outlook, I sometimes flag specific emails using the follow-up function.  This causes the item to appear in the task list, until either the item is marked completed or the email is deleted.

I now realize that if a flagged email in my inbox gets archived, then it disappears from the task list.  So is there a way to:

1 Change the archive setting to not archive flagged items?
2 OR  change the task list to pick up flagged items from both the Inbox and the Archived Inbox?

We do have Exchange 2010 SP3 servers 2 CAS, 2MBX in a DAG, one server role for each datacenter, we have archive policies to archive user's email therefore we have databases for regular and archive emails

Just a side note,  When client flag an email a month ago, it does not show up in the archive folder's flag listing.  The flag listing box only shows emails that are today moving forward.  

How can the client show past flagged emails?

Please respond to all the 3 questions above

Thanks in advance

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Franki