plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BSqlServer%2B%E3%83%86%E3%83%BC%E3%83%96%E3%83%AB%E3%81%AB%E5%88%97%E3%82%92%E8%BF%BD%E5%8A%A0
plugin=diff is not implemented.