mapping a string containing xml in BizTalk
<p>I have an xml document with a node that may optionally contain a string of escaped xml. I'd like to be able to transform that content using xsl in a BizTalk map. Any suggestion how?</p>

<p>I've tried:</p>

<ul>
<li>msxsl:node-set(string). This creates a nameless single node with no content.</li>
<li>The document() function using a url prefix of 'data:text/xml' as suggested by helderdarocha <a href="https://stackoverflow.com/questions/23767097/xslt-reading-a-param-thats-an-xml-document-passed-as-a-string">here</a>.</li>
<li>for-each selecting the text() of the node containing the string</li>
<li>using xpath() in an orchestration to extract the string then make a multipart message. It won't let me use an xmlDocument message as one of the messages in a multipart message transform.</li>
</ul>

<p>Do I have to use a C# helper assembly to accomplish this?</p>