For me the jail looks like this on Opensuse 11.1:
--- schnipp ---
[roundcube]
# 0.3 and up plugin-support
enabled = false
port = http,https
filter = roundcube
action = iptables-multiport[name=roundcube, port=http,https]
sendmail-whois[name=RC-Webmail, dest=root@weiss-du-doch.nett, sender=fail2ban]
logpath = /srv/www/htdocs/webmail/logs/userlogins
--- schnapp ---
Rgds.