Outlook and Offline Folders using IMAP

I'm running Outlook 2007. It seams to support the IMAP protocol reasonably well. However, I can't figure out how to move messages between folders when I'm offline (it gives an error message saying I can't, see below). This same operation works fine in MS Windows Mail (the equivalent of Outlook Express that ships with Windows Vista) and Mozilla Thunderbird. It's clearly not a limitation of IMAP.

I can download messages and read and delete them when I'm offline. I just can't move them between folders unless I'm online. Since Outlook synchronizes any changes to a folder when it reconnects to the IMAP server, and since I can read the messages in the folders, it obviously has the technology to do this. What am I missing?

As things are now, I can't process my mail when I'm offline - I need to read and file every message to clear out my Inbox. If I can't do that, I can't keep my work life organized. This all works just fine when working I'm online. But, as many of you know, while sitting on a plane, it's a great time to process e-mail and there's no chance of working in online mode midflight. For similar reasons, I would prefer to use Outlook to Windows Mail or Thunderbird - I want to flag messages as To Do's, and perform other functions that require the messages to be in Outlook.

Thanks for any help,

Error Messages
If I set Outlook to Offline mode (note I am not trying to move the folder, just an individual message):
Cannot move the items. The folder 'Inbox' cannot be selected. This may be because of a limitation of your IMAP server or the folder may have been deleted or moved.

If I leave Outlook in Online mode, but just physically sever it from the network: