reconstruct not seeing empty subfolders with messages

[Hal Huntley]

I'm new to Cyris IMAP but I do have some experience with Sun's IMAP,  so 
I know some of the commands.

We have Cyrus IMAP Server 2.1.13.  I did not set it up, but I've been 
asked to add some more messages to a person's IMAP account.  We acquired 
a tar file of some email messages from another location.  The message 
store appears to be the right type of each message number followed by a 
dot (.).  I've untarred these messages in to a user's area as a 
subfolder.  There are many subfolders in this original folder as well as 
sub-subfolders.

Here's a representation of the issue.

username -> user account folder
   norne    -> top level folder
      foo    -> sub folder (usually does not have messages but might)
         bar   -> sub-sub folder (may or may not have messages)

If there are messages  at the "foo" level, they are seen fine.  But if  
the "foo" level is empty of messages, but has sub-folders, none of the 
sub-folders are seen and thus none of their messages are seen.

As the cyrus user, I've done a "reconstruct -r -f 
user.username.username.norne".  (To get us started on making things 
work, we did a "touch cyrus.index" in each directory to make things work 
with the reconstruct.).  It looks like all the "cyrus.index", 
"cyrus.cache" and "cyrus.header" files are created appropriately.  
However, the IMAP client (in this case Thunderbird) does not see any 
folders beyond the "foo" level folder -- that is all the sub-sub-folders 
at the "bar" level (and below) are not see -- and those are the ones 
that contain most of the messages.

The message base is very large. There are about 480,000 messages in all 
the folders totaling almost three gig of disk space and about 3500 folder

Is there any way I can get the folders to be seen?  I noticed someone in 
a previous post asking about a "reconstruct -m" capability which the Sun 
IMAP uses to get the list of all the folders in an IMAP structure.  Is 
that what may be needed here? Thoughts and suggestions welcome.

Hal Huntley
SRI International