StoreBundle
    Controller
         CheckoutController.php
Payment
    PayUBundle
        Controller
            PayUController.php

use PaymentPayUBundleControllerPayUController;

Attempted to load class "PayUController" from namespace "PaymentPayUBundleController".
Did you forget a "use" statement for another namespace?

php app/console generate:bundle --namespace=PaymentPayUBundle
php app/console generate:bundle --namespace=PaymentStoreBundle

StoreBundle
    Controller

Payment
    PayUBundle
        Controller