Wiele profili użytkowników w django-userena

Próbuję utworzyć wiele profili dla Userena - każdy użytkownik może mieć tylko jeden typ profilu. Po innych dyskusjach używam dziedziczenia wielu tabel, ale kiedy to robię, nie mogę zapisać danych do pochodnych modeli. Wszystko kończy się jako CommonProfile, co nie powinno być możliwe / dozwolone. Przykładowy kod:

wmodels.py:

# models.py
# This is an example of how i've attempted to get 
# multiple user profiles working with Userena
from django.contrib.auth.models import User
from django.db import models
from userena.models import UserenaLanguageBaseProfile

class CommonProfile(UserenaLanguageBaseProfile):
    """Common fields for 2 user profiles: Spam and Eggs"""
    user = models.OneToOneField(User)
    common_field = models.CharField(max_length=100)

    @property
    def is_spam(self):
        """Find out if this is a Spam user"""
        try:
            self.spamprofile
            return True
        except SpamProfile.DoesNotExist:
            return False

    def get_real_type(self):
        """return the real model"""
        if self.is_spam:
            return self.spamprofile
        else:
            return self.eggsprofile

class SpamProfile(CommonProfile):
    spam_field = models.CharField(max_length=20)

class EggsField(CommonProfile):
    eggs_field = models.SmallIntegerField()

wforms.py

# forms.py
# This is the form to sign up a Spam Type Person

from django import forms
from userena.forms import SignupFormTos
from . models import CommonProfile, SpamProfile

class SpamSignupForm(SignupFormTos):
    """signup a Spam Person"""
    common_field = forms.CharField(label='what is your quest')
    spam_field = forms.CharField(label='what kind of spam are you')

    def clean(self):
        cleaned_data = super(SpamSignupForm,self).clean()
        #do stuf, same idea for clean_<field>
        return cleaned_data

    def save(self):
        """Save the SpamProfile"""
        user = super(SpamSignupForm,self).save()
        common_profile = user.get_profile()
        spam_profile = SpamProfile(commonprofile_ptr=common_profile)
        spam_profile.spam_field = self.cleaned_data['spam_field']
        spam_profile.save()
        return spam_profile