title: WSO2 DOCTYPE not allowed calling REST Api
body: <p>i m working with this proxy:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;proxy xmlns="http://ws.apache.org/ns/synapse"
         name="PubMedDataProxy"
         transports="https,http"
         statistics="disable"
         trace="disable"
         startOnLoad="true"&gt;
     &lt;target&gt;
        &lt;inSequence&gt;
           &lt;call&gt;
              &lt;endpoint&gt;
                 &lt;http method="get"
                   uri-template="http://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=omim&amp;amp;Mdb=pubmed&amp;amp;id=230900"/&gt;
              &lt;/endpoint&gt;
           &lt;/call&gt;
           &lt;log level="custom"&gt;
              &lt;property name="MyLOg" expression="//eLinkResult/DbFrom/text()"/&gt;
           &lt;/log&gt;
           &lt;respond/&gt;
        &lt;/inSequence&gt;
        &lt;outSequence&gt;
           &lt;send/&gt;
        &lt;/outSequence&gt;
     &lt;/target&gt;
     &lt;description/&gt;
  &lt;/proxy&gt;
  </code></pre>
  
  <p>i get this exception:</p>
  
  <pre><code>TID: [0] [ESB] [2015-05-21 13:45:34,838] ERROR {org.apache.synapse.transport.passthru.util.RelayUtils} -  Error while building Passthrough stream {org.apache.synapse.transport.passthru.util.RelayUtils}
  org.apache.axiom.om.OMException: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[2,142]
  Message: DOCTYPE is not allowed
      at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:296)
      at org.apache.axiom.om.impl.llom.OMDocumentImpl.getOMDocumentElement(OMDocumentImpl.java:109)
      at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:570)
      at org.apache.axiom.om.impl.builder.StAXOMBuilder.getDocumentElement(StAXOMBuilder.java:566)
      at org.apache.axis2.builder.ApplicationXMLBuilder.processDocument(ApplicationXMLBuilder.java:81)
      at org.apache.synapse.transport.passthru.util.DeferredMessageBuilder.getDocument(DeferredMessageBuilder.java:118)
      at org.apache.synapse.transport.passthru.util.RelayUtils.builldMessage(RelayUtils.java:107)
      at org.apache.synapse.transport.passthru.util.RelayUtils.buildMessage(RelayUtils.java:82)
      at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:68)
      at org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:239)
      at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.mediateFromContinuationStateStack(Axis2SynapseEnvironment.java:556)
      at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:198)
      at org.apache.synapse.core.axis2.SynapseCallbackReceiver.handleMessage(SynapseCallbackReceiver.java:488)
      at org.apache.synapse.core.axis2.SynapseCallbackReceiver.receive(SynapseCallbackReceiver.java:170)
      at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
      at org.apache.synapse.transport.passthru.ClientWorker.run(ClientWorker.java:225)
      at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
      at java.lang.Thread.run(Thread.java:745)
  Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[2,142]
  Message: DOCTYPE is not allowed
  ...
  </code></pre>
  
  <p>Calling the service in a normal REST client i get the XML result withouth any problem. </p>
  
  <p>The issue occured when the proxy tries to parse the resulting xml. Indeed removing the Log mediator with the property inside the proxy returns the result correctly.
  What am i missing?</p>