I was wondering if it would be possible to only have ISPConfig control the email settings, mainly because I would prefer to configure the rest the settings by hand. During install it said that it might make changes to httpd.conf and other conf files, all of which have already been set up correctly.
ISPConfig can normally not be used for email only configuration. If you only want to exclude the configuration of you apache webserver, you can make a backup of your apache configuration, install ISPCOnfig and then restore your old apache configuration. ISPConfig writes only once during setup in your httpd.conf or apache(2).conf file.
