.NET and W2K salting

[Greg Verby]

I have been doing some kerberos testing using
a W2K KDC and also a .NET KDC. I am seeing some differences 
when it comes to how these two "salt" the password
for key generation using DES-CBC-MD5 encryption.
The W2K seems to pickup whatever is in the
userPrincipalName field in AD and use that as salt,
while .NET ignores the userPrincipalName and
uses the host name (host/compname at REALM) instead.

Anyone has an idea what is going on here? Are there
any documentation on what the KDC should use as salt?

Thank you,
Greg