I have a problem with a multi-lingual site and SEO Plugin

I set the languages en, de, it, and HTTP_Accetpt_language as default and checked Multi-lingual in Options/General
Then I enabled the SEO plugins seo_locale, dynamic-locale, sitemap-extenden.

With this configuration I got a multi-lingual sitemap (3 versions of each URI), but the flag switch does not work: when I use a English browser I get the English version of my site, but when I click on the Italian or German flag the site is reloaded, but it is still in English.
The same happen if I use an Italian or German browser: I get the site in the correct languages, but then I cannot change the language using the flags. The only way to switch the language is to add manually “?locale=it_IT” or “?locale=de_DE” to the URL.

Well, if I remove the dynamic-locale plugin, the flag selector disappear (and I could live with that), but the problem now is that I get a sitemap without the 3 languages.

Did I make anything wrong in the setting?
I tried all that with both official themes Basic and Zenpage.
Any suggestion?

Thank you

Have you checked that the "http accept" option on hte language option is not set? Otherwise the browser picks the language based on its own setting.

Yes, I have disabled the option HTTP_Accept_Language, but I still have that problem.
Now regardless of the browser language I get always English (because I set English as default language). But still I cannot switch languages using the flags on the botton. If I click on the German or Italian flag, the site is reloaded, but the language is still English.

The only way to change language is adding "?locale=de_DE" to the URL.
Anyway, when I switch to German in that way, I cannot anymore switch to IT or EN by clicking on the flags.

I tried with Firefox, IE, Chrome... clrearing the browser cache, with anonym (privat) browser setting... always the same problem.

The flag switching works only if I disable the seo_locale plugin... but of course then I get a not-SEO sitemap.

Please post a link to the site in question.

http://foto.portanapoli.com

I can see it on your site and we also can sort of reproduce it ourselves. Seem that that seo-locale plugin is somehow interferring here indeed. We will investigate that (no ticket needed).

Just to add: It is recommended to use subdomains for multilingual sites so you get really different urls for each language.

Thank you for the help.

I would have liked to set subdomains for the languages, but the site is already a subdomain.

Or as alternative I should create the subdomain foto-de and foto-it for German and Italian...I'll think about that.