zend framework2 - How to make ZfcUser use an abstract db_adapter -

i'm using zend framework 2 , i've installed module zfcuser.

everything working correctly until i've decided add second db adapter in config/autoload/global.php

<?php return array(   'db' => array(     'adapters' => array(       'cleardb' => array(         'driver'         => 'pdo',         'dsn'            => 'mysql:dbname=secret;host=secret.com',         'driver_options' => array(           ...         ),       ),       'other' => array(...)     )   ),   'service_manager' => array(     'abstract_factories' => array(       'zend\db\adapter\adapterabstract'       => 'zend\db\adapter\adapterabstractservicefactory',     ),   ), ); 

now, zfcuser can't find default db adapter.

in zfcuser.global.php i've updated line:

'zend_db_adapter' => 'cleardb' 

this error when try login:

an alias "zfcuser_zend_db_adapter" requested no service found. 

your appreciated.