How Can I Incorporate Profiles in CiviEvent Backend?
this isn't a direct answer to the Q but may be what you want. At the top of Events registration page you should be able to see eg Welcome Joe Doe. (Not Joe Doe, or want to register a different person?) (eg at demo site)

If you click on that option you should then get to a url with cid=0 such as http://d46.demo.civicrm.org/civicrm/event/register?cid=0&amp;reset=1&amp;id=3 and this should allow a back-end user to register someone using the same Profiles etc that anyone would use via the front end. 

Is that what you need?