autocreating folders with special chars stored in mysql-userdb

[Hajo Locke]

Hello,

i use dovecot 2.2.18 and do some tests with an utf8 mysqlbackend.
I use MySQL to authenticate Users and for retrieving some individual 
settings like autocreating folders etc. by userdb-settings in user-query.
Yet no problems with standard language. Now i try to provide 
userdb-settings in exotic languages.

My MySQL table uses utf8 charset. I store some data in my userdb-column.
Here an polish example: "namespace/inbox/mailbox=example 
namespace/inbox/mailbox/example/name=postępować 
namespace/inbox/mailbox/example/auto=subscribe"

Result is a new folder in dovecot, but in client every special char ę 
and ć is replaced with a "?"
I seems that at some point a conversion to latin1 is performed which 
ruins the utf8 chars.
Creating a folder postępować  by imap-client is no problem.

Hmm, what should i do now? I dont know how to influence dovecot to 
process retrieved utf8 data furthermore as utf8.
Which charset is using dovecot when connecting to mysqldb and how to 
take influence?

Thanks,
Hajo