Getting Raw Request XML

I'm writing a RESTful services application that receives XML in its
POST and PUT requests. It's great that Rails parses out the XML into
the params hash, but occasionally I'd rather deal with the raw request
XML instead. How do I get at that?

Also, when writing functional tests for controllers is there a way to
send in the raw XML instead of the hash? In other words, something
like this:

def test_create
  post :xml => '<person><first-name>bob</first-name><last-name>smith</