IIRC, it simply worked for me. Instead of a password, the passphrase was being asked.
All I had to do was a normal login via SSH previously to get the known_hosts stuff sorted.
.''. Philipp Huebner <debalance@debian.org> : :' : pgp fp: 6719 25C5 B8CD E74A 5225 3DF9 E5CA 8C49 25E4 205F
. '
HP: http://www.debalance.de, Skype: philipp-huebner
`- ICQ: 235-524-440, Jabber: der_schakal@jabber.org