Laravel & NuSOAP problem

Hi,

I'm having an interesting problem regarding Laravel 5.2 and NuSOAP.

When defining a NuSOAP service in an inline route closure function, the NuSOAP web service works fine without any problems:

routes.php:

Route::any('api', function() {

    require_once ('nusoap.php');
    $server = new \nusoap_server();

    $server->configureWSDL('TestService', false, url('api'));

    $server->register('test',
        array('input' => 'xsd:string'),
        array('output' => 'xsd:string'),
        'xsd:demo');

    function test($input){
        return $input;
    }

    $rawPostData = file_get_contents("php://input");
    return \Response::make($server->service($rawPostData), 200, array('Content-Type' => 'text/xml; charset=ISO-8859-1'));

  });

client

require_once('nusoap.php');

$client = new nusoap_client('http://.../api?wsdl', true);

$result = $client->call("test", "just a string");

print_r($result); exit();

just a string

However, when moving this code to a dedicated controller:

routes.php:

Route::any('api', 'SoapController@server');

SoapController.php:

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class SoapController extends Controller {

    public function __construct() {
    }

    public function server() {
       // NuSOAP service code here 
    }

}

...the following error message is returned:

"method 'test' ('test') not defined in service('' '')

What could cause this behaviour? Could it be a middleware that's blocking access when the code is in a controller?

Do you have any ideas?

Thanks!