Short answer: Even after 6 month there is no working sync-solution available.

Ok, ok... some people do install a local groupware-server to sync their phones to their 10 appointments each month...

It seams to be an utterly complex development project to compare two textfiles (n900-calendar-"db"-export, akonadi-sql-result) and sync them.

Yeah I know - may the force be with me and do it myself... thanks.