How to restore POP3 Messages to iPad

Hello everyone, I had to restore my iPad, and now all the email messages are gone. I have a POP email account, which means that the emails are stored on the iPad, but wouldn't they get included in the backup which iTunes and iCloud make? I have tried a restore from iCloud backup and restore from iTunes backup, only to see that the emails aren't reappearing...

If anyone can help me out on this issue, it would be greatly appreciated.

Thanks a lot in advance!