Symfony 2中的自定义autoescaper

Question

I need to add to Symfony 2 default autoescaper an ability to escape double curly brackets {{ and }}. So it should work without any modifications inside twig templates.

I've tried to add custom escaper as

$twig->getExtension('Twig_Extension_Core')->setEscaper('angular-html', $escaper);

and replace default escaping strategy "html" with custom "angular-html"

class AngularEscapingStrategy
{
    public static function guess($name)
    {
        $strategy = \Twig_FileExtensionEscapingStrategy::guess($name);
        return ($strategy === 'html') ? 'angular-html' : $strategy;
    }
}

So it works, but twig built-in functions like form_row or nl2br require escaper name to be equal 'html' to work properly:

new Twig_SimpleFilter('nl2br', 'nl2br', array('pre_escape' => 'html', 'is_safe' => array('html'))),

Is there any other way to extend default "html" escaper and keep its name?