Things have changed a little bit in ES. The way they've done it allows you to have more flexibility than 7.x. Not only can you add usage rights to the form, but you can do anything you want to it before you render it (call a DB, apply policy, apply RE, apply security, etc).
When you create a xfaForm variable in ES, you can go under Advance Setting and assign it a render service. This service is responsible in delivering the form back to the end user.
The render service can simply be a render form (using LC Forms) or can be a whole process that render a form, add reader extension rights, add a policy,ect.
Right now, you are probably using the sample render service which just renders the form. What you can do is change that service and add a reader extension operation to it, or just create you own render service (by creating a new process).
I would suggest to take a look a the one you're probably using under Sample - Forms/RenderPDFForm