it's contained in the web.sitemap file. it can be a bit fiddly as you also need to amend the stings in the \App_GlobalResources\SiteMap.resx file as well. once you understand the relationship between them both, it's 'kinda' clear'. of course, if you're doing multi language stuff, dont forget the SiteMap.it(or whatever).resx file as well.
hope this is what you were referring to, otherwise, i'm stumped :D