Active Resource custom method using POST

I've written a small piece of code that is supposed to place an order in a order handling system. get, put and delete functions are working great but I cannot get post to function at all... the error I get back from the code below is 400 (bad request). I think it has something to do with the headers but I don't know how to get more info out of this. Is there a problem with the way I am handling the post method?

Thank you for your input!! Ben

I may just go to the command line with curl - that seems to work without a hitch. Also, for anyone looking at creating a POST body, the code I posted previously for converting a hash to POST body can be completely replaced with {hash}.to_param. In my case: body = input.to_param

Good luck -