For completeness of the topic, Django 1.7 (finally) supports using a custom reverse manager, so you can do something like that (just copying from the django docs):
from django.db import models
class Entry(models.Model):
objects = models.Manager() # Default Manager
entries = EntryManager() # Custom Manager
b = Blog.objects.get(id=1)
b.entry_set(manager="entries").all()