el purkka.py

                elif isinstance(field, models.ForeignKey) and\
                        field.rel.limit_choices_to:
                    key = field.rel.get_related_field().name
                    choices = field.rel.limit_choices_to
                    info.choices = list()
                    for choice in field.rel.to._default_manager.filter(**choices).values():
                        info.choices.append( (choice[key], unicode(choice.values()[0]),) )

                    info.shortName = '%s_id' % info.shortName
                    info.fullName = '%s_id' % info.fullName

                    setattr(clazz, 'get_%s_display' % info.shortName,  lambda x: getattr(x, field.name))