public function toXMLString()
 {
     $str = '';
     $str .= '<ns:DoReferenceTransactionReq>';
     if ($this->DoReferenceTransactionRequest != NULL) {
         $str .= '<ns:DoReferenceTransactionRequest>';
         $str .= $this->DoReferenceTransactionRequest->toXMLString();
         $str .= '</ns:DoReferenceTransactionRequest>';
     }
     $str .= '</ns:DoReferenceTransactionReq>';
     return $str;
 }
 public function toXMLString()
 {
     $str = '';
     $str .= '<urn:DoReferenceTransactionReq>';
     if ($this->DoReferenceTransactionRequest != null) {
         //prop is not a collection
         //prop is complex
         //prop is not enum
         //does not contain attribute or is attribute
         $str .= '<urn:DoReferenceTransactionRequest>';
         $str .= $this->DoReferenceTransactionRequest->toXMLString();
         $str .= '</urn:DoReferenceTransactionRequest>';
     }
     $str .= '</urn:DoReferenceTransactionReq>';
     return $str;
 }