Unable to use django-mssql provider

Does anyone know how to use the django-mssql provider? I set the requirements, but I can't get it to work.

Without sqlserver_ado in settings.py it imports a fine:

(testenv) C:\Users\Robin\test>python manage.py shell
Python 2.7.2 (default, Jun 12 2011, 14:24:46) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> import sqlserver_ado
>>> ^Z

With the database set to use sqlserver_ado in settings.py:

(testenv) C:\Users\Robin\test>python manage.py shell
ImproperlyConfigured: 'sqlserver_ado' isn't an available database backend.
Try using 'django.db.backends.XXX', where XXX is one of:
    u'mysql', u'oracle', u'postgresql_psycopg2', u'sqlite3'
Error was: cannot import name InterfaceError

EDIT:

Django == 1.5 Django-MSSQL == 1.5b1

EDIT 2:

Looking at the source for django-mssql shows that it is trying to import an InterfaceError from django.db.utils, which is not in Django 1.5