I also have same problem as Morphinex...I can't access webmail (installed through Tools), because I get user name or pw wrong (I created a user, with email, ftp, webspace, etc).
This is Telnet test:
Connected to x-174-30-41.vps.virtuo.it.
Escape character is '^]'.
220 x-174-30-41.vps.virtuo.it ESMTP Postfix (Debian/GNU)
250-AUTH LOGIN PLAIN
I also tried to send and email from an external link to new address.
PS: FTP works fine!