Assocation preload of has many through discards some attributes

When eager loading a has many through association, some attributes are ignored. For example, given

class Author < AR:Base
  has_many :posts
  has_many :comments, :through => :posts, :order => 'created_at desc', :conditions => '...', :include => :author

then Author.find xxx, :include => :comments will not honour the :order, :conditions & :include options, which would have been respected if the comments association was loaded normally