During the installation phase, it's possible to tell to ispconfig not use the modphp and suphp? For me these modes are useless because I'm using apache with mpm event, so I need to uninstall them.
ISPConfig uses php-fcgi. mod_php and suphp are just php modes that get offered for websites, so you don't have to install them.
Thanks I have also installed the roundcube mail, how I can convert the mod php of the vhost(https://www.howtoforge.com/tutorial/roundcube-installation-on-debian-8-jessie/) for fcgi?
I don't have any ready-made and tested instructions for that. Probably the easiest way would be to create a website in ispconfig e.g. for webmail.yourdomain.tld and then install roundcube into that website and let ispconfig handle the php-fcgi setup for you.