[horde] set shared address book as default

[lst_hoe02 at kwsoft.de]

Hello

we like to set the users "personal" address book as default for prefs  
in Turba/Kronolith/IMP. While it does somewhat work for IMP/Kronolith  
we have not yet succeed to set the "default_dir" and "sync_books" in  
Turba to use the shared (personal) address book. Is there any example  
how to set the shared addressbook in the prefs.local.php files?

Thanks

Andreas