This is for Drupal 7. There is a module called relation edit widget found under http:/[url removed, login to view] This module shall made going to work because i cant create the relation with this version. The module is based on the relations module. The module should view the child node edit form inline the parents node edit form. When now the parent is viewed the child is going to be viewed depending on the setting of the viewmode (hidden / fullnode). IIt should support that required field of the subform are only validated if the relation field is set to required.
So this module needs to be fixed and the feature from above needs to be implemented if they aren't.