diff --git a/README.md b/README.md
index 8d8a31c..a943a97 100644
--- a/README.md
+++ b/README.md
@@ -103,12 +103,12 @@ pass `--env` (`-e` in short) option to all registered commands:
 
 `ConfigServiceProvider` supports the following parameters:
 
-| Parameter                | Description                                                                                 | Default       |
-|--------------------------|---------------------------------------------------------------------------------------------|---------------|
-| `config.dir`             | Folder path with JSON files.                                                                | `null`        |
-| `config.params`          | Array of replacement tokens to use in configuration.                                        | `[]`          |
-| `config.env.default`     | Environment to use strictly on provider registration (ignores global environment variable). | `"local"`     |
-| `config.varname.default` | Name of global environment variable.                                                        | `"SILEX_ENV"` |
+| Parameter        | Description                                                                                 | Default       |
+|------------------|---------------------------------------------------------------------------------------------|---------------|
+| `config.dir`     | Folder path with JSON files.                                                                | `null`        |
+| `config.params`  | Array of replacement tokens to use in configuration.                                        | `[]`          |
+| `config.env`     | Environment to use strictly on provider registration (ignores global environment variable). | `"local"`     |
+| `config.varname` | Name of global environment variable.                                                        | `"SILEX_ENV"` |
 
 By default, service provider embeds tokens `__DIR__` and `__ENV__`, as well as all PHP environment variables (e.g.
 `REMOTE_ADDR`, `SERVER_NAME`, etc).
diff --git a/tests/Silex/Provider/ConfigServiceProviderTest.php b/tests/Silex/Provider/ConfigServiceProviderTest.php
index f98e90b..78c50cb 100644
--- a/tests/Silex/Provider/ConfigServiceProviderTest.php
+++ b/tests/Silex/Provider/ConfigServiceProviderTest.php
@@ -79,22 +79,22 @@ public function testBrokenConfigFile()
 
     public function testDefaultEnvironment()
     {
-        $custom = new \stdClass();
-
         $random = hash('adler32', uniqid());
         putenv('SILEX_TEST_VAR='.$random);
 
+        $custom = strrev($random);
+
         $app = new Application();
         $app->register(new ConfigServiceProvider(), [
-            'config.dir' => __DIR__.'/../../config',
-            '_custom'    => $custom,
+            'config.dir'    => __DIR__.'/../../config',
+            'config.params' => ['custom' => $custom],
         ]);
         $app->boot();
 
         $this->assertArrayHasKey('config', $app);
         $this->assertEquals('local', $app['env']);
         $this->assertEquals('%__ENV__%', $app['config']['env']);
-        $this->assertSame($custom, $app['_custom']);
+        $this->assertEquals($custom, $app['custom']);
 
         $dir = realpath($app['dir']);
         $this->assertNotSame(false, $dir);
@@ -116,6 +116,7 @@ public function testCustomEnvironment()
         $app->boot();
 
         $this->assertEquals('test', $app['env']);
+        $this->assertEquals('%custom%', $app['custom']);
         $this->assertEquals(__DIR__, realpath($app['dir']));
         $this->assertEquals(realpath($dir).'/test.json', $app['file']);
         $this->assertContains('<alex.lokhman@gmail.com>', $app['author']);
diff --git a/tests/config/local.json b/tests/config/local.json
index c2fa00c..5072a34 100644
--- a/tests/config/local.json
+++ b/tests/config/local.json
@@ -6,5 +6,6 @@
 
     "env": "%__ENV__%",
     "var": "%SILEX_TEST_VAR%",
-    "dir": "%tests_dir%/Silex"
+    "dir": "%tests_dir%/Silex",
+    "custom": "%custom%"
 }