anonymous registration creates user account

i have a site with running with entity registration.

Anonymous Users are allowed to make registrations. Is it possible to allow anonymous users to edit their own content after the registration is saved?
I try with rules to create a user account after the registration process with the Data from the registering user. This works perfect but how can i reference the registration content with the created account?

maybe there is a simpler solution.

or how can i change the author of a registration with the rules module after saving the registration?