encryption key in a separate USB

[Zenny]

Hi:

After bitten by the encryption-key-lost situation on two occasions
(once while upgrading from 10B3 to 10RC1
http://lists.freebsd.org/pipermail/freebsd-stable/2013-December/076335.html
,and after installing afresh 10.0-RELEASE
http://lists.freebsd.org/pipermail/freebsd-stable/2014-February/077195.html
), I am thinking of storing the encryption.key to a separate USB disk.

Any hints shall be appreciated! Thanks in advance.

/z