vacation plugin

[sup69]

Hello,
I m trying to set up vacation on roundcube (Ubuntu 10.10). I have installed vacation and vacation plugin.
I'm having some problem to make it work, it says it cannot connect to the ftp-server 'localhost'.
I do not understand the driver system (FTP, SSHFTP, setuid...).

Which kind of driver should i use for system users (no SQL)  and how configure it?
Is there no HOWTO which could explain easily the installation.

For information my server uses courier-imap + postfix with system users (no SQL).

Thanks for your help.