Trying to remove HTML layout from RXML templates

Hi you all,

I have a simple REST app with a controller method like this:
def index
    @sdrs = Sdr.find(:all)
    respond_to do |format|

The rxml is well constructed, however, what I get when the request is
through XML is the xml information surrounded by the layout of the app,
something like:
- <html xmlns="" xml:lang="en" lang="en">
- <head>
    <meta http-equiv="content-type" content="text/html;charset=UTF-8" />
    <title>Sdrs: index</title>
- <body>
   <p style="color: green" />

   <?xml version="1.0" encoding="UTF-8" ?>
- <sdrs>
- <sdr>

How can I say that I just want the xml output?

Either this:
layout 'application', :except => :create_with_ajax
or this: (some code is in the middle of
the page)