XHTML mime type

I’m trying to insert inline SVG in my XHTML pages but I realized that rails serves XHTML
pages with content-type header set to “text/html;
charset=utf-8”. It’s definitely not cool and it should be
“application/xhtml+xml, charset=utf-8”.
So I’ve added a mime type line in initializer :
Mime::Type.register “application/xhtml+xml”, :xhtml
I also modified my controllers to use xhtml mime type.
respond_to do |format|
format.xhtml # index.xhtml.erb
format.xml { render :xml => @users }
And finally rename my views *.html.erb became *.xhtml.erb.

This modifications works well but i have a few questions :

1 - Is there a more straightforward / elegant solution ?

2 - How can I handle browsers that don’t understand
application/xhtml+xml content type ?

Thanks in advance