[Users] Local folders for archived mails

[Adrian]

I have a lot of old/archived mails (too big for my IMAP server's free
disk space) that I'd like to access on one Claws installation.  I'd
like to have the mails physically on that machine's hard drive, and not
to sync with the IMAP server.  With this configuration I could see and
search very old mails, and move or filter a few to other folders, which
would be normal ones on the IMAP server. Is this possible?

I've tried setting up a local account but I can't make it show up.
Configuration/Change current account to the local one has no effect,
the normal IMAP account is the only one that's ever visible.  I also
tried setting up a POP3 account but that doesn't seem to allow you to
specify a local mail location.

Ideally these folders would be visible as within my default account,
but simply be local and not mirrored on my IMAP server.

Thanks
Adrian