Michal,
The .htaccess has the by defect rules uncomment :
########## Begin - 3rd Party SEF Section
############# Use this section if you are using a 3rd party (Non Joomla! core)
############# SEF extension - e.g. OpenSEF, 404_SEF, 404SEFx, SEF Advance, etc
#
RewriteCond %{REQUEST_URI} ^(/component/option,com) [NC,OR]
RewriteCond %{REQUEST_URI} (/|\.htm|\.php|\.html|/[^.]*)$ [NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.*) index.php
#
########## End - 3rd Party SEF Section
If the link is /content/view/4/2/?lang=en OpenSef+Artio Path converts correctly to a friendly url like /en/test.htm
If the link is /content/view/4/2/lang,en/ doesn't convert to anything and not found message appears
Perhaps it's possible to modify .htacess with some additional rule ... but I don't know how to do it.
Thanks in advance.