[Nuxeo-localizer] How to create .po files

[Gitte Wange]

Hello,

I new to Localizer (but familiar with gettext tough) ... 

I have created a product where I want to translate some daynames in the class 
before returned to the UI.

I have looked at the NuxWidgets product and seen how you created the 
Multilingual class ... so now I now how the text actual gets translated .. 

But I'm still wondering how to create the .po files ... 
I have tried using the zgettext.py script parsing it my .py file ... but the 
da.po file it creates have no message strings .. 

What am I doing wrong ?

TIA,
Gitte Wange