[RCU] Junk instead of Spam folder

I am using postfixadmin to manage users, and I instruct it to create a Spam folder:

$CONF['create_mailbox_subdirs']=array('Drafts','Spam','Sent','Trash'); $CONF['create_mailbox_subdirs_host']='localhost'; $CONF['create_mailbox_subdirs_prefix']='';

and when I log into dovecot, that is what I see:

b list "" *

• LIST (\HasNoChildren \Sent) "." Sent
• LIST (\HasNoChildren \Trash) "." Trash
• LIST (\HasNoChildren \Drafts) "." Drafts
• LIST (\HasNoChildren) "." Spam
• LIST (\HasNoChildren) "." INBOX

b OK List completed.

But Roundcubemail is showing:

 Inbox
 Drafts
 Sent
 Junk
 Trash

Any recommendation where to look to straighten this out?

thanks