Center menu items

[bleak]

Hi, I'd like to know if you can center the menu items. I've found 
options in themes like:

menu.items.justify:     center
menu.title.text.justify:  center
window.label.text.justify: center

The title indeed displays centered but not the menu items.
I've also tryed (by logic but without seeing it anywhere):

menu.items.text.justify:     center

I even tryed:

*justify: center

Nothing seems to make those menu items center. What am I doing wrong?