I'm trying to use this "Sendfax" method defined here:
https://ws.interfax.net/dfs.asmx?WSDL.  I can't seem to a set a
properly format the request however.  Previously I was using
SOAP::WSDLDriverFactory and was succesfully using the service, but
inside a rails application it could not find the "SOAP" module.  A
fair bit of time was spent with no resolution.

I read good things about SAVON (http://github.com/rubiii/savon) but I
can't seem to get it to work in a test or in a project.   If anyone is
familiar with Savon, I'd -really- appreciate some help as I am stumped
as to why this isn't working.

I have some straight-forward code:

def client
      @client ||= Savon::Client.new "https://ws.interfax.net/dfs.asmx?
WSDL"
end

def send_fax(username="foo", password="bar", fax_number=nil, data=nil)

      @response = client.sendfax do |soap|
         soap.body = {:Username => username,
                      :Password => password,
                      :FaxNumber => fax_number,
                      :FileData => data,
                      :FileType => "HTML"}
      end
 end