Custom IMAP account using a simple username without a domain

Hi everyone. I have just received my Supernote Manta and am thoroughly impressed. However, I have just tried adding a custom IMAP account and the device gives me a malformed account error. It expects the IMAP account to be of the form someuser@somedomain.end but my work imap login is just a username without the domain part. Is there a workaround to specify a custom IMAP account username without adding \@somedomain?