how to customise Emacs to recognise 13.10. as 13th of October this year instead of 2010-10-13?

[Gregor Zattler <telegraph@gmx.net>]

Dear org-moders,

today (2012-10-11) I yanked "Kommt am 13.10. um 14:00 zum" into
the date/time prompt: the date is recognised as "<2010-10-13 Mi
14:00>" instead of <2012-10-13 Sa 14:00> as I would expect since
I have the following customisations (excerpt):

(custom-set-variables
;[...]
 '(calendar-date-style (quote european))
;[...]
 '(diary-date-forms (quote ((day "\\. ?" month "\\. ?[^0-9]") 
                           (day "\\. ?" month "\\. ?" year "[^0-9]") 
                           (day "/" month "[^/0-9]") 
                           (day "/" month "/" year "[^0-9]") 
                           (backup day " *" monthname "\\W+\\<\\([^*0-9]\\|\\([0-9]+[:aApP]\\)\\)") 
                           (day " *" monthname " *" year "[^0-9]") 
                           (dayname "\\W"))))
;[...]
)

as part of my .init.el.


I thought the first diary date form would match this text but it
doesn't.  Even "Kommt am 13.10.2012 um 14:00 zum" is parsed as 
"<2010-10-13 Mi 14:00>".  I thought the second diary date form
would match this.

Before I realised this I captured several events with wrong dates.

Any Ideas?

Ciao, Gregor