When setting up the mail wizard on the iPhone you will have to add an account first … Tap on "Other"

and then on Add Mail Account.

Now enter your account information and tap on the "Save" button.

Thereby you can specify an eMail name and a description of your mail account.

Now you have to provide additional information that are required for creating the account. It's important that "IMAP“ is selected as protocoll.

Specify the EUserv server data for your incoming eMails.

The hostname is imap.euserv.de. Enter your username and your password.

Finally specify the hostname for the server responsible for the outgoing eMails (smpt.euserv.de).

Now you can use "Mail" and send/receive your eMails at EUserv.

Therefore choose "Settings" on your home screen and select „Mail, Contacts, Calendars“.

Tap on your mail account

and then on your user account.

Now tap on "Advanced“.

Now enter INBOX under "IMAP Path Prefix“ and save this setting.

Go to your inbox and tap on "Edit" and

finally tap on New Mailbox.

Give this mailbox a name and save it.

Now you have created a new mailbox.