Issue with virtual folder: partially see them and cannot subscribe

[dovecot at avv.solutions]

Hello Community,

I am trying to figure out hwo to use the virtual mailboxes, but remain a 
bit confused:

- I see the Virtual speudo-folder
- Eventuelly the name of the boxes underneath
- But cannot see more, nor subscrie to the virtual mailboxes

Dovecot:

# 2.2.29.1 (e0b76e3): /usr/local/etc/dovecot/dovecot.conf
# Pigeonhole version 0.4.18 (29cc74d)
# OS: Linux 4.4.50-v7+ armv7l Debian 8.0 ext4
auth_mechanisms = plain login
log_path = /dev/stderr
mail_attribute_dict = 
file:/sd/MAIL_IMAP_POP/%d/%n/Maildir/dovecot-attributes
mail_debug = yes
mail_gid = vmail
mail_location = maildir:/sd/MAIL_IMAP_POP/%d/%n/Maildir:LAYOUT=fs
mail_plugins = " virtual mail_crypt"
mail_uid = vmail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope 
encoded-character vacation subaddress comparator-i;ascii-numeric 
relational regex imap4flags copy include variables body enotify 
environment mailbox date index ihave duplicate mime foreverypart extracttext
namespace {
   inbox = yes
   location =   mailbox {
     special_use = \Drafts
     name = Drafts
   }
   mailbox {
     special_use = \Junk
     name = Junk
   }
   mailbox {
     special_use = \Sent
     name = Sent
   }
   mailbox {
     special_use = \Sent
     name = Sent Messages
   }
   mailbox {
     special_use = \Trash
     name = Trash
   }
   prefix =   name = inbox
}
namespace {
   hidden = no
   list = yes
   location = virtual:/sd/MAIL_IMAP_POP/%%d/%%n/Virtual
   prefix = Virtual/
   separator = /
   subscriptions = yes
   type = private
   name = virtual
}
passdb {
   args = /etc/dovecot/dovecot-sql.conf.ext
   driver = sql
}
plugin {
   mail_crypt_curve = secp521r1
   mail_crypt_save_version = 2
   sieve = 
file:/sd/MAIL_IMAP_POP/%d/%n/Sieve;active=/sd/MAIL_IMAP_POP/%d/%n/Sieve.active
}
service replication-notify-fifo {
   name = aggregator
}
service anvil-auth-penalty {
   name = anvil
}
service auth-worker {
   user = vmail
   name = auth-worker
}
service {
   unix_listener {
     group = postfix
     mode = 0666
     user = postfix
     path = /var/spool/postfix/private/auth
   }
   unix_listener {
     mode = 0600
     user = vmail
     path = auth-userdb
   }
   user = dovecot
   name = auth
}
service config {
   name = config
}
service dict-async {
   name = dict-async
}
service dict {
   name = dict
}
service login/proxy-notify {
   name = director
}
service dns-client {
   name = dns_client
}
service doveadm-server {
   name = doveadm
}
service imap-hibernate {
   name = imap-hibernate
}
service {
   inet_listener {
     port = 143
     name = imap
   }
   inet_listener {
     port = 993
     ssl = yes
     name = imaps
   }
   name = imap-login
}
service imap-urlauth {
   name = imap-urlauth-login
}
service imap-urlauth-worker {
   name = imap-urlauth-worker
}
service token-login/imap-urlauth {
   name = imap-urlauth
}
service imap-master {
   name = imap
}
service indexer-worker {
   name = indexer-worker
}
service indexer {
   name = indexer
}
service ipc {
   name = ipc
}
service {
   unix_listener {
     group = postfix
     mode = 0600
     user = postfix
     path = /var/spool/postfix/private/dovecot-lmtp
   }
   name = lmtp
}
service log-errors {
   name = log
}
service sieve {
   name = managesieve-login
}
service login/sieve {
   name = managesieve
}
service {
   inet_listener {
     port = 110
     name = pop3
   }
   inet_listener {
     port = 995
     ssl = yes
     name = pop3s
   }
   name = pop3-login
}
service login/pop3 {
   name = pop3
}
service replicator-doveadm {
   name = replicator
}
service login/ssl-params {
   name = ssl-params
}
service stats-mail {
   name = stats
}
ssl = required
ssl_cert = </sd/MAIL_IMAP_POP/_ssl/pi3tv.local.avv_server.crt
ssl_key =  # hidden, use -P to show it
userdb {
   args = /etc/dovecot/dovecot-sql.conf.ext
   driver = sql
}
protocol lmtp {
   mail_plugins = " virtual mail_crypt sieve"
   service replication-notify-fifo {
     name = aggregator
   }
   service anvil-auth-penalty {
     name = anvil
   }
   service auth-worker {
     name = auth-worker
   }
   service auth-client {
     name = auth
   }
   service config {
     name = config
   }
   service dict-async {
     name = dict-async
   }
   service dict {
     name = dict
   }
   service login/proxy-notify {
     name = director
   }
   service dns-client {
     name = dns_client
   }
   service doveadm-server {
     name = doveadm
   }
   service imap-hibernate {
     name = imap-hibernate
   }
   service imap {
     name = imap-login
   }
   service imap-urlauth {
     name = imap-urlauth-login
   }
   service imap-urlauth-worker {
     name = imap-urlauth-worker
   }
   service token-login/imap-urlauth {
     name = imap-urlauth
   }
   service imap-master {
     name = imap
   }
   service indexer-worker {
     name = indexer-worker
   }
   service indexer {
     name = indexer
   }
   service ipc {
     name = ipc
   }
   service lmtp {
     name = lmtp
   }
   service log-errors {
     name = log
   }
   service sieve {
     name = managesieve-login
   }
   service login/sieve {
     name = managesieve
   }
   service pop3 {
     name = pop3-login
   }
   service login/pop3 {
     name = pop3
   }
   service replicator-doveadm {
     name = replicator
   }
   service login/ssl-params {
     name = ssl-params
   }
   service stats-mail {
     name = stats
   }
}
protocol lda {
   mail_plugins = " virtual mail_crypt virtual"
   service replication-notify-fifo {
     name = aggregator
   }
   service anvil-auth-penalty {
     name = anvil
   }
   service auth-worker {
     name = auth-worker
   }
   service auth-client {
     name = auth
   }
   service config {
     name = config
   }
   service dict-async {
     name = dict-async
   }
   service dict {
     name = dict
   }
   service login/proxy-notify {
     name = director
   }
   service dns-client {
     name = dns_client
   }
   service doveadm-server {
     name = doveadm
   }
   service imap-hibernate {
     name = imap-hibernate
   }
   service imap {
     name = imap-login
   }
   service imap-urlauth {
     name = imap-urlauth-login
   }
   service imap-urlauth-worker {
     name = imap-urlauth-worker
   }
   service token-login/imap-urlauth {
     name = imap-urlauth
   }
   service imap-master {
     name = imap
   }
   service indexer-worker {
     name = indexer-worker
   }
   service indexer {
     name = indexer
   }
   service ipc {
     name = ipc
   }
   service lmtp {
     name = lmtp
   }
   service log-errors {
     name = log
   }
   service sieve {
     name = managesieve-login
   }
   service login/sieve {
     name = managesieve
   }
   service pop3 {
     name = pop3-login
   }
   service login/pop3 {
     name = pop3
   }
   service replicator-doveadm {
     name = replicator
   }
   service login/ssl-params {
     name = ssl-params
   }
   service stats-mail {
     name = stats
   }
}
protocol imap {
   mail_plugins = " virtual mail_crypt virtual"
   service replication-notify-fifo {
     name = aggregator
   }
   service anvil-auth-penalty {
     name = anvil
   }
   service auth-worker {
     name = auth-worker
   }
   service auth-client {
     name = auth
   }
   service config {
     name = config
   }
   service dict-async {
     name = dict-async
   }
   service dict {
     name = dict
   }
   service login/proxy-notify {
     name = director
   }
   service dns-client {
     name = dns_client
   }
   service doveadm-server {
     name = doveadm
   }
   service imap-hibernate {
     name = imap-hibernate
   }
   service imap {
     name = imap-login
   }
   service imap-urlauth {
     name = imap-urlauth-login
   }
   service imap-urlauth-worker {
     name = imap-urlauth-worker
   }
   service token-login/imap-urlauth {
     name = imap-urlauth
   }
   service imap-master {
     name = imap
   }
   service indexer-worker {
     name = indexer-worker
   }
   service indexer {
     name = indexer
   }
   service ipc {
     name = ipc
   }
   service lmtp {
     name = lmtp
   }
   service log-errors {
     name = log
   }
   service sieve {
     name = managesieve-login
   }
   service login/sieve {
     name = managesieve
   }
   service pop3 {
     name = pop3-login
   }
   service login/pop3 {
     name = pop3
   }
   service replicator-doveadm {
     name = replicator
   }
   service login/ssl-params {
     name = ssl-params
   }
   service stats-mail {
     name = stats
   }
}
protocol pop3 {
   service replication-notify-fifo {
     name = aggregator
   }
   service anvil-auth-penalty {
     name = anvil
   }
   service auth-worker {
     name = auth-worker
   }
   service auth-client {
     name = auth
   }
   service config {
     name = config
   }
   service dict-async {
     name = dict-async
   }
   service dict {
     name = dict
   }
   service login/proxy-notify {
     name = director
   }
   service dns-client {
     name = dns_client
   }
   service doveadm-server {
     name = doveadm
   }
   service imap-hibernate {
     name = imap-hibernate
   }
   service imap {
     name = imap-login
   }
   service imap-urlauth {
     name = imap-urlauth-login
   }
   service imap-urlauth-worker {
     name = imap-urlauth-worker
   }
   service token-login/imap-urlauth {
     name = imap-urlauth
   }
   service imap-master {
     name = imap
   }
   service indexer-worker {
     name = indexer-worker
   }
   service indexer {
     name = indexer
   }
   service ipc {
     name = ipc
   }
   service lmtp {
     name = lmtp
   }
   service log-errors {
     name = log
   }
   service sieve {
     name = managesieve-login
   }
   service login/sieve {
     name = managesieve
   }
   service pop3 {
     name = pop3-login
   }
   service login/pop3 {
     name = pop3
   }
   service replicator-doveadm {
     name = replicator
   }
   service login/ssl-params {
     name = ssl-params
   }
   service stats-mail {
     name = stats
   }
}

Any tip/suggestion?
I tried several configs from https://wiki2.dovecot.org/Plugins/Virtual
Example 1:
Virtual/Deleted/dovecot-virtual:
*
   deleted

Example 2
Virtual/All/dovecot-virtual
*
-Trash
-Trash/*
   all

Thanks!