title: xades4j: how to produce an signature with a transform in the signedproperties reference
body: <p>I received an example xades signature that I have to reproduce using xades4j ("like a template").</p>
  
  <p>The example signature is this (an excerpt):</p>
  
  <pre><code>&lt;ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#" Id="xmldsig-qualifyingproperties-yada-yada"&gt;
      &lt;ds:SignedInfo&gt;
          &lt;ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/&gt;
          &lt;ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"/&gt;
          &lt;ds:Reference URI="#xmldsig-signedproperties-yada-yada"&gt;
              &lt;ds:Transforms&gt;
                  &lt;ds:Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315#WithComments"/&gt;
              &lt;/ds:Transforms&gt;
              &lt;ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/&gt;
              &lt;ds:DigestValue&gt;yada-yada-yada-yada-yada-yada-yada&lt;/ds:DigestValue&gt;
          &lt;/ds:Reference&gt;
  (...)
  </code></pre>
  
  <p>I know that this reference is not xades compliant, because there is no attribute Type there.</p>
  
  <p>My issue is with the Transform in that Reference. I'm not able to find how can I set this option with xades4j. Can this be done?</p>
  
  <p>Also, I don't know if that is here make sense, because at the signature top, it says that the canonicalization method is one then in the signedproperties reference it says the canonicalization method is another one... Am I reading this correctly?</p>