Django 1.5 custom user model plus admin.autodiscover() breaks app
I set up a brand new empty project with a custom user model and attempted to recreate the situation, which led to a diagnosis: we had added the django-usertools package to the project, which has not been updated for Django 1.5 and apparently conflicts with custom user models.  Removing that package from the installed apps list in settings resolved the issue.
I have a custom user model (it's actually named User as I didn't see any need to name it otherwise) in my Django 1.5c1 project (currently running on the latest from the Django 1.5 branch on github).  AUTH_USER_MODEL is defined in my settings properly, so the auth module works correctly and I can log in etc. fine.
However, with the custom user module enabled, the admin site doesn't work.  When I add admin.autodiscover() to my urls.py, every page on the site (not just admin pages) throws a NotRegistered exception and says The model User is not registered.  The traceback shows that admin.autodiscover() is trying to call admin.site.unregister(User), apparently before it has registered that model.
I tried renaming my user model to something other than User, but it didn't seem to work.  I also tried creating my own admin.py for that app, and then I tried manually registering my custom User model with the custom UserAdmin model specified in admin.py before admin.autodiscover() ran, but that actually caused a separate exception saying that User was already registered.
What should I try next in order to get admin.autodiscover() working?