Hi,
SHA2 certificates are supported on
ISA long as they are generated with a Cryptographic Service Providers supported by CryptoAPI.
Find the list of CSP supported by CryptoAPI in this article:
http://msdn.microsoft.com/en-us/library/windows/desktop/bb931357(v=vs.85).aspx
And yes, you need to install KB968730.
http://blogs.technet.com/b/pki/archive/2010/09/30/sha2-and-windows.aspx
Best Regards,