/**
  * Find the child node matching the given node
  * A method with the same signature MUST exist in MFElement for the recursion to work fine
  * @param MFElement $oRefNode The node to search for
  * @param string    $sSearchId substitutes to the value of the 'id' attribute 
  */
 public function _FindChildNode(MFElement $oRefNode, $sSearchId = null)
 {
     return MFElement::_FindNode($this, $oRefNode, $sSearchId);
 }
 /**
  * Find the child node matching the given node
  * @param MFElement $oRefNode The node to search for
  * @param bool      $sSearchId substitutes to the value of the 'id' attribute 
  */
 public function FindExistingChildNode(MFElement $oRefNode, $sSearchId = null)
 {
     return MFElement::FindNode($this, $oRefNode, $sSearchId);
 }