Problem with principal names

[Mordur Ingolfsson]

Hi,

I'm new to kerberos.  I wish to use Kerberos for password
verification on a cyrus imap installation. My problem is, that since  we
serve multiple domains, the usernames are in the form "username at domain.name"
Is it possible to create principals in the form "user/username at domain.name@REALM.NAME," and if not, is there a workaround? Or am I perhaps misunderstanding the whole thing terribly?

Thanks,

Mordur