[Dovecot] Dovecot / Win8 Mail App Folder Subscription Issue

Win8 RTM Mail App now supports IMAP. I am running Dovecot 1.2.15 on a Debian Stable server.

The App works fine except the list of folders displayed seems to be a random subset of all my folders. I can't figure out how it's picking which folders to show, or how to change what's subscribed. Editing the "subscriptions" folder in ~/Maildir/ doesn't seem to have any impact.

Any suggestions on how to troubleshoot or narrow done this issue?

I posted to a Microsoft forum but was told the Mail App will only support official email providers.