Routing in Silex/Symfony. Providing a default route

I'm attempting to do something using Silex (which uses the Symfony routing component - so the answer may be applicable to Symfony as well)

I am adding Silex to a legacy application to provide routing but I need to respect the existing applications default implementation for loading files (which is simply to load the file from the file system form the URL specified).

edit: for clarification: Existing file is loaded from the file system, as an include within an parent template, after a series of bootstrapping calls have been made.

What I'm finding is that in the absence of a defined route to match the legacy pages, Silex is throwing an exception.

I really need a way to provide a default (fallback) mechanism for handling those legacy pages - but my pattern has to match the entire url (not just one fragment).

Is this possible?

// Include Silex for routing    
require_once(CLASS_PATH . 'Silex/silex.phar');

// Init Silex
$app = new Silex\Application();

    // route for new code
    // matches for new restful interface (like /category/add/mynewcategory)

    $app->match('/category/{action}/{name}/', function($action, $name){
        //do RESTFUL things
    });

    // route for legacy code (If I leave this out then Silex
    // throws an exception beacuse it hasn't matched any routes

    $app->match('{match_the_entire_url_including_slashes}', function($match_the_entire_url_including_slashes){
        //do legacy stuff
    });

    $app->run();

This must be a common use case. I'm trying to provide a way to have a RESTFUL interface alongside legacy code (load /myfolder/mysubfolder/my_php_script.php)