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; }