Translation of layout set properties

Hello,

I created a custom layout set to display customized properties: size, date of creation and date of last modification.

All is good, except that i need to translate column headers to different languages. I added them in collection renderer settings (displayed proeprties: contentlength, created, modified)

I know how to do translate using Portal Content Translation, but these translation are for portal content items only. How do i translate those  i.e column header names)

Any help will be appreciated!