"user." in mailbox names

[Marten Lehmann]

Hello,

we are currently using dovecot for IMAP and POP3 and we would like to 
migrate to Cyrus. The email-address is the login, e.g. 
test at testdomain.de. When I'm creating accounts in cyrus, I have to 
prepend "user." to the mailbox names (thus user.test at testdomain.de). But 
when a user logs in with test at testdomain.de as before, he doesn't see 
his folders. Doesn't do cyrus the mapping to user.test at testdomain.d?
If not, why do I have to create mailboxes with "user." then?

Regards
Marten