Use of date filter plugin - Match & timezone parameters

Hi,

I'd like to have some complementary informations regarding the use of the date plugin. I'm unable to force the timezone of a date to be at CET time. Can someone tell me which value of the timezone parameter should I use to recover the correct time format ?

For example : entry is Jul 28 09:33:40. I want this output : 2015-07-28T07:33:40.000Z

I managed once to have another timezone but it was for Los Angeles and it was weird (2015-07-28T16:33:40.000Z).

Here's the configuration:
date {
match => [ "timestamp_orig", "MMM dd HH:mm:ss", "MMM d HH:mm:ss", "ISO8601" ]
timezone => "CET" # I used Europe/Paris, Europe/Berlin but all failed
locale => "en"
target => [ "date" ]
}

Another intel is I'mm using Logstash 1.4.2.

Does Logstash 1.4.2 follow the values from the following web page http://joda-time.sourceforge.net/timezones.html ?