Changing LocalizedString of My Computer

After reading, I think it was, a TechMail I changed the LocalizedString of my computer to %username% on %computername% which displayed MyUserName on MyComputerName as the caption of the My Computer icon. After formating I can’t reproduce this. My syntax must be wrong. Now I’m getting the literal “%username% on %computername%” and not what these variables represent. Also, what are other variables that can be used here and what are other places that they can be used? (a link to an article(s) willdo for the what and where information).