The best way is to add new module position - article how to do it you will find on our wiki. We add styling support for language switcher module in following update.
How make that the upper menu change according with the Language selection? it has been create the mainmenu-PT and mainmenu-FR, but don't change the default menu...
Please send me a screenshot with configuration of one menu item which should NOT be visible. It is for sure set to only one language ? The language filter plugin is configured to always load one of the languages as a default ?