Roundcube for a lot of subdomain

[LucaB.]

Hello,
On our centos 6.6 server we have a roundcube installation on /var/www/roundcube/ that offers a lot of subdomain like mail.domain.com. It offers them by the config.inc.php file. In this file we add an element in the 'include_host_config' array for each subdomain, for example:
'mail.domain.com' => 'domain.inc.php'
We also have /etc/httpd/conf.d/roundcube.conf file that offers /var/www/roundcube/ with its alias and nameserver.
Now we want to use roundcube installation of Plesk (12.5.30).
How could we use roundcube installation of Plesk with our configuration?


Thanks.

Luca