I'm using 2.0.0.rc.7, I'm writing a rich client app using backbone.js, so I'm just passing json data between the client and server. Mongoid serializes objects and embedded objects with "_id" field. This is fine, except when trying to update an embedded object. I'm passing these embedded objects with "_id" set instead of "id", but the objects do not update. If the objects instead use "id" they update as expected.

example of the data I'm posting:
{:issue => {:_id => "4d49c9963c850c5715000001", :title => "some problem", :comments_attributes => [ {:_id => "4d2dffca3c850c04ca000006", :message => "some updated message"}] }}