[Zope] i18n site and search robots

Hi, This is not strictly speaking a Zope problem, but certainly lots amond you faced and fixed this. I made a i18n site with Localizer that runs fairly good, including its i18n search engine. But what about external searche engine robots (google, infossek...) How to "tell" them that they may browse and index the pages in french, english, spanish (...), changing their http header "Accept-Language" ? Many thanks in advance --Gilles