I remember that I replied this request somewhere long time ago. It is difficult to guide you to do it, so please send us admin and FTP account of your site via Support ticket and let us know :
1. On what event database table we can get the data to display in registration form.
2. The solution here is that we will create a custom field and then get data from the database table, generate that custom field. You can then assign that custom field to the event you want.
