Acknowledge copyright of a journal for registration

I was wondering how can I get a new user to acknowledge some copyright issues of a journal. so that after checking a box or so and say one agrees with the copyright the user can register.

I am using OJS 2.4.8.

This parallels the discussion here:

The first post here describes most of what you want to do, especially if you just want to require the agreement without permanently storing it as a new user profile field.