[Dovecot] virtual user directories?

[Mike]

I'm installing dovecot and hope to migrate my users from
a POP3 system soon. I have the users in LDAP and LDAP is
working, dovecot is using LDAP to authenticate my tests.
What I'm trying to find is a setting when a user is
authenticated by LDAP and dovecot, and that user directory
does not exist in the location I have given for the private
name space, I want dovecot to create the directory. Mentioning
in a log that it created a directory is ok, but I want it
to create the directory. I do not want to have to create
the directories by hand (easy to do, I know, but that's not
the point).

Is there a way to tell dovecot to create any missing directories
for authenticated users?

Mike