cancan breaks scoped mass assignment

Hi all,

I just installed cancan on a new project and found out that it creates
some problems with the new scoped mass assignment features of rails 3.2
.

Basically, in my User model I create some attr_accessible attributes in
order to avoid users to edit their roles or other sensitive information.
From the administration I allow admins to edit those protected
attributes by passing :without_protection => true on creation and update
of new users.

This works just fine, but adding cancan load_and_authorize_resource to
my controller triggers a "Can't mass-assign protected attributes:
...stuff..." . This happens also when using something like
User.new(params[:user], :role => :admin)

I really can't figure out how to solve this, so any help would be very
appreciated!

Thanks in advance.