Hello,
I have downloaded the vacation plugin for roundcube.  I have the default settings.  I can not get the vacation tab to appear in the roundcube interface.  
My config.ini
[default]
driver = "ftp"
subject = "Default subject"
body = "default.txt"
[dotforward]
binary = "/usr/bin/vacation"
flags = ""
message = ".vacation.msg"
database = ".vacation.db"
alias_identities = true
set_envelop_sender = false
always_keep_message = true
main.inc.php has this line:
$rcmail_config['plugins'] = array('vacation');
Note I do not have squirrelmail installed.  Also, using Sendmail.
Please advise.