Finally, a patch fork that adds support for namespaces, heredoc and the support of # as comment character for this version of php-mode. To apply it, download the patch and execute this simple command line

patch php-mode.el < php-mode.el.diff
  

After restarting Emacs, you should obtain something like this

# is finally rendered correctly
namespace Pi\Truc\Bidule;
use Pi\XmlTag, Pi\Lib\String;
use Pi\Glob, Pi\Lib\String as PiStr;
Pi\XmlTag::test();
$xml = new Pi\XmlTag();
function foo(Pi\XmlTag $bla, PiStr $blo) {}
echo 'L\'ananas';