title: SOAP on Rails, can not call a method with WSDL using Savon
body: <p>I want to use a financial institution webservice to "verifyTransaction" 
  The method gets two strings as input and return a double as output.</p>
  
  <pre><code>double verifyTransaction (
  String      RefNum, 
  String      MerchantID
  )
  </code></pre>
  
  <p>I used Savon in rails 3.1 to call the method.</p>
  
  <pre><code>client = Savon::Client.new do |wsdl|
      wsdl.document = "https://acquirer.sb24.com/ref-payment/ws/ReferencePayment?WSDL"
  end
  
  response = client.request :wsdl, "verifyTransaction" do
    soap.body ={"RefNum" =&gt; "ReferenceNumber", "MerchantID" =&gt; "MymerchantId"}
  end
  </code></pre>
  
  <p>but the I got this error:</p>
  
  <pre><code>Savon::SOAP::Fault ((env:Client) caught exception while handling request: unexpected encoding style: expected=http://schemas.xmlsoap.org/soap/encoding/, actual=)
  </code></pre>
  
  <p>Any thought on how to solve this?</p>