Selectively cache models with cache_money

Instead, in the initializer cache_money.rb

class ActiveRecord::Base
  is_cached :repository => $cache
end

      

        
        
        
      

    

I want to be able to selectively cache only certain models (the reason our custom model breaks memcached is because it is usually too large to serialize properly).

class User < AR::Base
  is_cached :repository => $cache
end

      

        
        
        
      

    

This, however, throws an exception.

Any idea on how to do this?