First of all, I need to apologize to Horrific. I volunteered to be a Beta tester a while back and am just now getting around to installing the plugin. I will give some feedback once it is installed.
Anyhow, I followed the steps in Post #20. Things were going smooth until I log in to Roundcube. I see the Account tab under the Settings menu. When I click on three of menu options on the left (General, Autoreply, & Junk), the Roundcube error message appears at the top of the window.
The error message reads "Soap Error: Could not connect to host".
I eventually resolved the problem by copying the config.inc.php.dist file to config.inc.php. I don't recall seeing that step specified in the steps in Post #20. That copy step is pretty typical when dealing with Roundcube Plugins.
Additionally, since my test server setup has Roundcube installed as a vhost on the same physical machine as ISPConfig3, I had to use localhost instead of the FQDN in the plugin config file. If I used the FQDN, I still received the Soap Error message.
$rcmail_config['soap_url'] = 'http://localhost:8080/remote/';
Finally, the demo site that Horrific gave me a link for showed a lot more functionality than this plugin currently provides. I remember seeing the ability to interact with the SPAM filter settings more directly such as White/Black lists. Is that functionality planned for this plugin or am I expecting too much?