How can I browse old mails in an IMAP folder? Both the build-in mail client (Android 2.1) and K-9 mail, display the most recent n messages received during the last m days, where m and n are configuration items. Messages older than m days are invisible.

It's certainly sensible to hide old mail my by default, but how cannot I lookup an old message in INBOX or another folder? Even if the INBOX folder is huge, retrieving all headers should be an option.
In K-9 Mail, if you scroll down in your inbox, it shows the option "Load up to n more", and by repeating this you can go back further and further.