title: Talend tRESTClient requires Document data type in schema
body: <p>I'm using the tRESTClient  to call a REST service to post a JSON string (with records).  The tRESTClient component does not allow me to use a custom schema that matches my string.  it says:</p>
  
  <p>the method <code>getDocument()</code> is undefined for the type String</p>
  
  <p>It seems is trying to execute the <code>getDocument</code> against the schema but the input schema is a STRING not a DOCUMENT data type.  </p>
  
  <p>If I use a tMAP to try to convert my json String to a Document, I get this error:</p>
  
  <blockquote>
    <p>Type Mismatch: cannot convert from String to Document</p>
  </blockquote>
  
  <p>how does one convert a string to a document? this is a json string such as this:</p>
  
  <pre><code>{"names:[{"fname":"edgar"},{"fname":"jose"},{"fname":"peter"}]}
  </code></pre>