Your first attempt,, was close :-) I think it should probably be. This will create a redlink, and on the page it links to you should write a sentence or so describing, in Greek, the generality of pages that will be in that language.
The first part "Category" tells the system to create or use an existing category page. The second part requires a translation, so that Greek speakers can find related pages in their own language.
To ensure consistency we ask for category definitions to be added to tables - new translators can then follow those as guidelines. I've added a column in Category_Translation,_Esperanto_to_Suomi(fi) for you. It looks squashed at the moment, but when you start adding definitions it should re-align the content.
Hope that helps 
Thanks very much, it seems that i had nt got how it works. Now i added the caqtegories: http://userbase.kde.org/Category_Translation,_Esperanto_to_Suomi(fi)
But i have a problem with the link, i cannot add the category:
I have the message "invalid token (badtoken)"
I see that in the page of the category "Για να ξεκινήσετε/el" the link is :
I tried to add this one to with the html letters but it did nt work.
KDE UserBase Wiki 