Wanderlust, offlineimap & mu on ubuntu

[Zip Random <ziprandom@googlemail.com>]

Hi all, 

after fighting my way through the scattered ressources about setting up wanderlust i know have a fairly usable mail-client inside emacs. i am using offlineimap to fetch my various accounts into a maildir structure and mail-utils (mu) for indexing and search. 

there are some things missing on the way to total delight and I hope to find some last answers on this list: 

1. New Mails

Do you use offlineimap with the idle function to get mails instantly? do you have some offlineimap hooks configured to refresh the folder-view on mail arrivals? i want new mails to popup in the folder and summary view immediatly without having to manually refresh the view. i think hooks are more elegant than cron-like refreshs. i also dont'want to refresh all folders, as this takes some 30s in my setup. generally how to you solve this issue?

2. mu indexing, searching and virtual folders
 Do you have emacs (wanderlust) configured to automatically run: mu index upon changes to the maildir? in my setup I have to run it manually whicht renders virtual folders ( for example: [flag:unread]!mu ) senseless. also: when i use mu powered search in wanderlust i often/most of the time get the error: 
    Wrong Type Argument: stringp, nil 

thank you for any responses. 

Zip Random