How to change standard date

[Cecil Westerhof]

I would like to display the standard displayed date to local date, but I
can not get it to work.

I tried:
  (setq gnus-treat-date-local head)
But this gives:
    gnus-treat-predicate: "head" is not a valid value

I tried:
  (setq gnus-treat-date-local "head")
But then all headers are displayed, instead of only the default ones.

I tried:
  (setq gnus-treat-date-local t)
This looks the best, but there is an hour difference with 'W T l'.

So what is the correct way to get default the local date displayed?

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof