Virtuelle Dovecotuser werden von Postfix nicht verwendet

Hallo zusammen,

ich habe den Authentifizierungsmechanismus von dovecot auf die /etc/dovecot/users gestellt.
Soweit so gut. Mit dem Webmailer kann ich mich auch als diese User anmelden und Mails versenden.
Beim Mailempfang gibt es allerdings Probleme, da Postfix meint folgendes in den Logs sagt:

Recipient address rejected: User unknown in local recipient table;

Ich habe schon etwas recherchiert um dieses Problem zu lösen. Leider konnte ich mir damit nicht helfen. Weiß jemand was genau zu tun ist?
Hier die main.cf von Postfix:

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = ipv4
mail_owner = postfix
mailbox_size_limit = 1073741824
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
message_size_limit = 20971520
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mydomain = example.de
myhostname = srv0.example.de
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.10.1/README_FILES
sample_directory = /usr/share/doc/postfix-2.10.1/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_tls_exclude_ciphers = MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL
smtp_tls_loglevel = 2
smtp_tls_mandatory_ciphers = high
smtp_tls_mandatory_exclude_ciphers = MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL
smtp_tls_mandatory_protocols = !SSLv3, !SSLv2
smtp_tls_protocols = !SSLv2, !SSLv3
smtp_tls_security_level = may
smtpd_banner = $myhostname ESMTP
smtpd_helo_restrictions = reject_invalid_hostname
smtpd_recipient_restrictions = permit_mynetworks,permit_auth_destination,permit_sasl_authenticated,reject
smtpd_sasl_auth_enable = yes
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_tls_cert_file = /etc/ssl/mail.example.de.crt
smtpd_tls_exclude_ciphers = MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL
smtpd_tls_key_file = /etc/ssl/mail.example.de.key
smtpd_tls_loglevel = 2
smtpd_tls_mandatory_ciphers = high
smtpd_tls_mandatory_exclude_ciphers = MD5, DES, ADH, RC4, PSD, SRP, 3DES, eNULL, aNULL
smtpd_tls_mandatory_protocols = !SSLv3, !SSLv2
smtpd_tls_protocols = !SSLv2 !SSLv3
smtpd_tls_received_header = yes
smtpd_tls_security_level = may
unknown_local_recipient_reject_code = 550

Danke schon mal im Vorraus und Lg

# create a admin user for virtual mailboxes
[root@mail ~]# useradd -u 20000 -s /sbin/nologin vmail
[root@mail ~]# vi /etc/postfix/main.cf
# line 164: comment out
#mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
# add to the end
# if specify multiple domains, specify comma or space separated
virtual_mailbox_domains = srv.world, virtual.host
virtual_mailbox_base = /home/vmail
virtual_mailbox_maps = hash:/etc/postfix/virtual-mailbox
virtual_uid_maps = static:20000
virtual_gid_maps = static:20000