Duplicate Inbox with dimap and Domino server

I have recently started using KMail (I have tried an old 3.5.10 version and 
the latest 4.3.2 on Debian unstable) to access mail on a Lotus Domino 
server.  

The mailbox is enormous, and using normal IMAP was impossible as it kept
trying to repopulate the entire folder on every fetch.  So I tried 
disconnected IMAP which in most respects works much better.

The only problem I have is that the Inbox appears twice.  And it thinks that
both of them are inboxes, not folders.  As there is large quantities of spam
coming though on this mailbox, deleting them all twice is a waste of time.

When I first tried this I found some references to this being a known problem,
but now when I google I can not find anything that looks relevant (I am 
probably asking the wrong question).  Does anyone know if this is a known
problem (if so what is the bug number), and what progress is being made to
fix it.

If it would help, I can provide remote access to a Domino server to fix the
problem is a KMail developer would find that useful.

Regards

David