prova con questa:
\A(?=\S*?[A-Z])(?=\S*?[a-z])(?=\S*?[0-9])(?=\S*?[\W])\S{8,11}\z
Michael Denny | Microsoft Visual C# MVP
http://blogs.dotnethell.it/Regulator/
http://dennymichael.net
http://mvp.microsoft.com/mvp/Michael%20Denny-5000735
Twitter: @dennymic