Symfony 2使用代理返回错误的url

I'm working on an Silex project and run into an issue with wrong url's when calling the site with a proxy.

Sitename without proxy: http://sitename.com/someFile.php

Sitename with proxy: https://sslsites.com/sitename.com/someFile.php

$_SERVER['HTTP_X_FORWARDED_HOST']: 'sslsites.com'

I set the Trusted Proxies in my index.php

Request::setTrustedProxies(array('sslsites.com'));

composer.json

"silex/silex": "1.0.*@dev",
"twig/twig": "~1.12",
"symfony/twig-bridge": "~2.2",
"symfony/validator": "~2.2",
"symfony/form": "~2.2",
"symfony/config": "~2.2",
"symfony/translation": "~2.2",
"symfony/locale": "~2.2",
"symfony/yaml": "~2.2",
"symfony/filesystem": "~2.2",
"symfony/finder": "~2.2",
"swiftmailer/swiftmailer": "~4.3",
"doctrine/dbal": "~2.3"

When running "url('category')" in a twig-Template, i'd expect:

https://sslsites.com/sitename.com/category

But I see instead

https://sslsites.com/category

I don't want a quick and dirty solution. Can anyone give me a hint?

When using the component as part of the framework you can the router.request_context.base_url parameter, like so..

parameters:
    router.request_context.base_url: my/path

Which would lead me to believe that you would be able to use..

if ($baseUrl = $app['request']->server->get('HTTP_X_FORWARDED_HOST')) {
    $app['request_context']->setBaseUrl($baseUrl);
}

I assume the best place to do this would be when you are creating the app but I may be wrong as I've only had a cursory glance at Silex.