Comment # 2 on bug 878929 from Luiz Angelo Daros de Luca

Just to help other users, this is the workaround I use:

  <sysconfig config:type="list">
    <sysconfig_entry>
      <sysconfig_key>DISPLAYMANAGER</sysconfig_key>
      <sysconfig_path>/etc/sysconfig/displaymanager</sysconfig_path>
      <sysconfig_value>kdm</sysconfig_value>
    </sysconfig_entry>
  </sysconfig>