plugin=diff is not implemented.
http://yellow.ribbon.to/~tuotehhou/index.php?%2BWindows%2BIP%E3%82%A2%E3%83%89%E3%83%AC%E3%82%B9%E3%81%A8%E3%83%9B%E3%82%B9%E3%83%88%E5%90%8D%E3%82%92%E3%83%9E%E3%83%83%E3%83%94%E3%83%B3%E3%82%B0
plugin=diff is not implemented.