Ruby On Rails :: Controlling Parameters Passed In Rubyamf (rails + Flex)?

How do I control what parameters are passed in a RemoteObject method? I noticed that when I directly download and run the code from this site, saving an object results in the following parameter set being passed back:

Processing PostsController#save (for 127.0.0.1 at 2011-02-01 23:34:55) [POST] Parameters: {0=>{"post"=>#<Post id: nil, title: "a", body: "b", created_at: nil, updated_at: nil>}, "post"=>#<Post id: nil, title: "a", body: "b", created_at: nil, updated_at: nil>}

[Code]...