composerで入れたパッケージがautoloadで見つからなくてエラーになっちゃう場合の対処法

{
    "require": {
        "pear/http_request2": "2.2.1"
    }
}

$ php composer.phar update

<?php

require 'vendor/autoload.php';

$request = new HTTP_Request2();
print_r($request);

$ php test.php
php test.php 
PHP Warning:  require_once(Net/URL2.php): failed to open stream: No such file or directory in /Users/tsukui/Desktop/foo/vendor/pear/http_request2/HTTP/Request2.php on line 24
PHP Fatal error:  require_once(): Failed opening required 'Net/URL2.php' (include_path='/Users/tsukui/Desktop/foo/vendor/pear/pear_exception:.:/usr/lib/php/pear') in /Users/tsukui/Desktop/foo/vendor/pear/http_request2/HTTP/Request2.php on line 2

{
    "require": {
        "pear/http_request2": "2.2.1"
    },
    "include-path": [
        "vendor/pear/net_url2",
        "vendor/pear/http_request2"
    ]
}

$ php composer.phar update

$ php test.php 
HTTP_Request2 Object
(
    [observers:protected] => Array
        (
        )
中略
    [adapter:protected] => 
    [cookieJar:protected] => 
)