Hello again,

you did it correctly to specify your preferred domain in Google as http://www.domain.com, always indicate the preferred domain in Google.

If you login to http://www.domain.com/administrator and you find all links in the sitemap as http://domain.com that probably means that in the Joomla configuration.php you have hardcoded the domain in the $live_site variable. Normally the domain is reflected and propagated automatically by Joomla itself when you login as http://www.domain.com/administrator

I suggest to fix it in Joomla itself, although you can change it easily in JSitemap configuration using the parameter visible below.

About the meta title, you have to see it changed in the browser page title of the same page. Notice that if the link is different (http://www.domain.com/link.html and http://domain.com/link.html) obviously it won't work. So first of all fix links issue.

Regards.