[Dovecot] Xlist in userdb, Foldernames with whitespace?

[Hajo Locke]

Hello,

i use dovecot 2.1.7 and exported all my XLIST FolderSettings to userdb
Whole Story is here:
http://dovecot.org/list/dovecot/2013-March/089209.html

This is all successful, but there is one problem left.

I use lines like this to realize individual XLIST Foldernames in usedb:

namespace/inbox/mailbox=Sent namespace/inbox/mailbox/Sent/name=Sent 
namespace/inbox/mailbox/Sent/auto=subscribe 
namespace/inbox/mailbox/Sent/special_use=\sent

My problem is to allow Foldernames with whitespace in it f.e. Sent Messages
I tried to put these names in quotes in this line or mask the blank with 
backslash but nothing was working.
Dovecot ist not accepting these settings:

dovecot: imap: Debug: Added userdb setting: namespace/inbox/mailbox="Sent 
Messages"
dovecot: imap: Debug: Unknown userdb setting: 
plugin/namespace/inbox/mailbox/"Sent Messages"/auto=subscribe
dovecot: imap: Debug: Unknown userdb setting: 
plugin/namespace/inbox/mailbox/"Sent Messages"/name="Sent Messages"
dovecot: imap: Debug: Unknown userdb setting: 
plugin/namespace/inbox/mailbox/"Sent Messages"/special_use=\sent


How to code folders with whitespace etc. in my userdb settings?
I tried a lot but nothing was correct.

Thanks,
Hajo