RESTful web services return 403 forbidden for uc_order_product

I’m using ubercart and RESTful web services module. When I query for node, uc_order, user, etc., it returns data correctly, but when I query for “uc_order_product” I always get 403 Forbidden.

Inspecting the module I’ve found that

user_access('access resource uc_order_product') 

returns false, and

$resource->access($access_op, $id) 

returns false too. I have granted access to this resource, and then, I don’t know why it gives always 403 forbidden. If I change the module and bypass this, I can get uc_order_products well. I’ve tried with admin too, and the same, 403 forbidden for the admin.

What could I do in order to grant access to uc_order_product?