Whenever Outlook is connected to Exchange, the RSS feeds in Outlook must come from Exchange and must be stored in Exchange. To me, that is a flaw in the design because some users may want Exchange to manage their RSS and others may want CFL to manage them. My opinion is that Outlook/Exchange users should be given the option (optionally locked down by a network administrator through Group Policy or whatever, of course) to choose where they want their RSS feeds stored. I also think that a combination or blended ability would be nice to have the CFL sync to Exchange on whatever machines you're using, however this could be a large technical hurdle for Microsoft. I just don't know.
To speak specifically to your issue: I would say that your best bet (using Outlook/Exchange and IE on two different machines) would be to set your feeds up in Outlook so that they are stored in Exchange and do not set them up in IE or the machine-specific CFL store. That way, you always have a current copy of your feeds (and your read-state) on whichever machine you're using. The only issue for this would be when you are unable to connect to Exchange for whatever reason, but since you're using Outlook over RPC, that should only happen when you're unable to connect to the Internet, which would also keep CFL from updating your feeds. I assume you're using Outlook in Cached mode, so reading the feeds you have already downloaded shouldn't be a problem even if you're unable to connect.
I hope this answers your question. Feel free to reply and ask again if I haven't covered what you're looking for.
Thanks for the question!
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