$data = file_get_contents('testing.doc');

$soap->SetLocalTemplate(
   array(
        'template' => base64_encode($data),
        'format'   => 'doc'
    )
);

$soap->CreateDocument();
        $result = $soap->RetrieveDocument(
            array(
                'format' => 'txt'
            )
        );

$data = $result->RetrieveDocumentResult;
file_put_contents(file.txt', base64_decode($data));

echo base64_decode($data);