Have a look at the
document in the URL you posted. Page 2 sets the stage in terms of the .Net vs Java changes.
TM1 Web will act as a client on behalf of a user looking to access a kerberized service, in this context a TM1 server on Windows in a given Microsoft Kerberos realm. In Microsoft Windows,a Kerberos realm is defined implicitly by a Windows domain. Therefore a user from a Windows domain which is trusted (implicit or explicit domain/forest trust required) by the domain in whichthe TM1 server is running can authenticate to the TM1 server through Kerberos. However, theuser is not accessing the TM1 server directly but is using TM1 Web. For this to work, the Windows user will have to provide their Windows user name and password to TM1 Web which will run the authentication process on the user's behalf and if successful, the user is considered authenticated to TM1 Web as well.
Architect is using Integrated Login (options 2/3), not SSO per TM1Web
This said, Integrated, Seamless login using your Kerberos token you already have been issued would be much friendlier!