Django-reversion и родственная модель

У меня есть следующие models.py

class Contact(models.Model):
    pass

class Link(models.Model):
    pass

class Relationship(models.Model):
    # Documentation
    __doc__ = _(u'Stores a relationship between 2 contacts.')
    # Attributes
    from_contact = models.ForeignKey(Contact, related_name='from_contacts', verbose_name=_(u'first contact'), help_text=_(u'The first contact implicated by the relationship.'))
    link = models.ForeignKey(Link, related_name=u'relationships', verbose_name=_(u'relationship link'), help_text=_(u'The relationship link between both contacts.'))
    to_contact = models.ForeignKey(Contact, related_name='to_contacts', verbose_name=_(u'second contact'), help_text=_(u'The second contact implicated by the relationship.'))

    # Meta-data
    class Meta:
        verbose_name = u'Relationship'
        verbose_name_plural = u'Relationships'
        unique_together = ('from_contact', 'link', 'to_contact')

Используя класс-представление Django и Revision Context Manager, я могу создавать ревизию в любое время, когда создаю новое соотношение между двумя контактами

# part of my views.py
class RelationshipCreateView(LoginRequiredMixin, CreateView):
    template_name = u'frontend/relationships/relationship-create.html'
    model = Relationship
    form_class = RelationshipForm

    def get_success_url(self):
        return reverse_lazy('contact-detail', kwargs={'contact_pk': self.kwargs['contact_pk']})

    def form_valid(self, form):
        contact = Contact.objects.get(pk=self.kwargs['contact_pk'])
        link = form.cleaned_data['link']
        other = form.cleaned_data['other']
        inverse = form.cleaned_data['inverse_relationship']
        relationship = None
        if not inverse:
            relationship = Relationship(
                from_contact=contact,
                link=link,
                to_contact=other
            )
        else:
            relationship = Relationship(
                from_contact=other,
                link=link,
                to_contact=contact
            )
        with reversion.create_revision():
            relationship.save()
            reversion.set_comment(_(u'A relationship has been added between %(from)s and %(to)s' % {'from': relationship.from_contact, 'to': relationship.to_contact}))
        return HttpResponseRedirect(self.get_success_url())

Но только один из контактов получает ревизию (первый) и комментарий, прилагаемый к ней. Как Revision Context Manager можно использовать для создания обеих версий?