For a paypal express integration with payum in Symfony 3.1.4 I defined the storage in config.yml like this
AppBundle\Entity\Payment: { doctrine: orm }
Now I want to use the storage defined by the class "PaymentDetails" from paypal-rest payum. It is located under "../vendor/payum/paypal-rest/Payum/Paypal/Rest/Model/PaymentDetails.php". How exactly can I do this? How do i define a path in vendor to point to the class I need in config.yml or which folder structure would I have to copy to my "Resources"-folder to make it available?