Smooks freemarker transformation fails in SOA-P 5 if input data contains namespaces

Issue

We want to use Smooks to transform an XML stream into a different one using the templating mechanism provided by Freemarker. The service is exposed as ESB webservice:

      <actions inXsd="SmooksIssueWS.xsd" mep="RequestResponse">
        <action name="print-input-soap-message" class="org.jboss.soa.esb.actions.SystemPrintln" />
        <action name="transform" class="org.jboss.soa.esb.smooks.SmooksAction">
          <property name="smooksConfig" value="/smooks-res.xml" />
          <property name="resultType" value="STRING" />
         </action>
        <action name="print-xml-result" class="org.jboss.soa.esb.actions.SystemPrintln" />
      </actions>

Smooks transformation file (smooks-res.xml):

<?xml version='1.0' encoding='UTF-8'?>
<smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.1.xsd"
                      xmlns:ftl="http://www.milyn.org/xsd/smooks/freemarker-1.1.xsd"
                      xmlns:esbr="http://www.jboss.org/xsd/jbossesb/smooks/routing-1.0.xsd">

  <!-- Capture data from the incoming message into DOM models.  These are then avaiable to
       templating etc... -->
  <resource-config selector="sayHi">
    <resource>org.milyn.delivery.DomModelCreator</resource>
  </resource-config>
  <ftl:freemarker applyOnElement="sayHi">
      <ftl:template>/templates/soap-to-plain-xml.ftl</ftl:template>
  </ftl:freemarker>
</smooks-resource-list>

Freemarker template file (soap-to-plain-xml.ftl):

<root>
  <args>
   <arg>${sayHi.arg}</arg>
  </args>
</root>

When running this sample and providing input data using SoapUI, the transformation fails with the following ERROR:

ERROR [runtime] 
Error on line 3, column 11 in templates/soap-to-plain-xml.ftl
Expecting a string, date or number here, Expression sayHi.arg is instead a freemarker.ext.dom.NodeListModel
The problematic instruction:
----------
==> ${sayHi.arg} [on line 3, column 9 in templates/soap-to-plain-xml.ftl]
----------

Java backtrace for programmers:
----------
freemarker.core.NonStringException: Error on line 3, column 11 in templates/soap-to-plain-xml.ftl
Expecting a string, date or number here, Expression sayHi.arg is instead a freemarker.ext.dom.NodeListModel
    at freemarker.core.Expression.getStringValue(Expression.java:126)
    at freemarker.core.Expression.getStringValue(Expression.java:93)
    at freemarker.core.DollarVariable.accept(DollarVariable.java:76)
    at freemarker.core.Environment.visit(Environment.java:209)
    at freemarker.core.MixedContent.accept(MixedContent.java:92)
    at freemarker.core.Environment.visit(Environment.java:209)
    at freemarker.core.Environment.process(Environment.java:189)
    at freemarker.template.Template.process(Template.java:237)
    at org.milyn.templating.freemarker.FreeMarkerTemplateProcessor.applyTemplate(FreeMarkerTemplateProcessor.java:207)
    at org.milyn.templating.freemarker.FreeMarkerTemplateProcessor.visitAfter(FreeMarkerTemplateProcessor.java:179)