Problem viewing Fax Inbound msgs after migration Domino 5 --> 7

I’ve a problem viewing Fax Inbound messages on iNotes5 client after a migration of the Domino Server from release 5.011 to release 7.Everything works ok with mail clients that use dwa7, but can’t see the attachment on mail clients that use iNotes5.

The server logs ‘MIME to CD Conversion…’ but no error are displayed.

The only way to get things work is to set ‘Format preference for incoming mail’ to ‘Prefers Notes Rich Text’ in the Person document on the server. But this works only with the new incoming messages and not with the old ones.

Why did the migration introduced this problem?

How can I resolve it without migrating to dwa7?

Thanks! :o)