How to stop response from wrapping node lists with <elem>

[micsky]

SmartGWT 2.3 - RestDataSource
How to stop response from wrapping node lists with <elem> ?

<response>
  <data>
    <record>
      <id>123</id>
      <name>Name</name>
      <children>
        <child>
          <elem>
            <childId>555</childId>
            <childName>name</childName>
          </elem>
          <elem>
            <childId>666</childId>
            <childName>name</childName>
          </elem>
        </child>
      </children>
    </record>
  </data>
</response>

I have tried setUseFlatFields but with no luck.