FreeBSD: Upgrade from 8.2 to 9.0

If you use this command to upgrade to latest release FreeBSD 9.0:

$ freebsd-update -r 9.0-RELEASE upgrade

You might see following error:

The update metadata is correctly signed, but failed an integrity check. Cowardly refusing to proceed any further.

This error indicate that it cannot accept % and @ characters which appear in FreeBSD 9 . To [...]