Assign a custom theme (template) to a category

I use two categories NEWS and PROJECTS. For the landingspage PROJECTS I want to use a two column layout. I found out I have to use the theme "Nickel".

The instructions for doing this is as follows:

You can create different theme folders in the folder /templates/isis/html/com_easyblog/themes/

I have put the complete "NICKEL" directory with all the files in the above directory. Not working.
I have put this also in [mytemplate} directory. Not working.

EasyBlog does not see this custom template / theme.

As I only want this layout for PROJECTS and not for NEWS, I am stuck. Any help appreciated (maybe a better instruction).