On the phone go into settings and mail and add a new Exchange account.
Enter your email address, username and password. It will probably complain about a security certificate but click OK and then you can manually add the server details below:
Server: exchange.gohost.it
Domain: CORE
Username: as supplied or normally the first part of your email address before the @
Password: as supplied
Use SSL: ON
That should be all you need. You can the adjust the Sync settings to syncronise mail, contacts and calendar as required.
Note: Push email does use more battery so if you don't need this, it may be better to switch of and syncronise manually or on a schedule
