Hello Andrew,
I do not have answer to your question, but below is some information which I got from PTC since Ialso wanted to try the same on 9.1M020 build
"I just wanted to add one more information for this call. You can check the below document for NTLM authentication (chapter 2 -page 4 and page 7) which allow users to log in without a prompt:<u>http://www.ptc.com/WCMS/files/78982/en/WCAdvDeployGuide.pdf</u>Also, I would like to inform you that there is a known issue/SPR#1687893 for NTLM authentication:The description of the SPR is as follows “Create and upload fails in DTI and with Pro/E when configured to authenticate with SSPI (NTLM) The error "missing CachedContentDescriptor" is thrown.”The workaround for the above issue is to use basic authentication instead of NTLM authentication.Once again the only authentication technique fully supported by PTC and fully tested with Windchill is HTTP Basic authentication. The use of any other authenticationmethods is the responsibility of the customer or the implementation team."
Let me know if you ( or anyone) find out more information
Regards,
Kamlesh