I have answered your question in the support thread you posted. Here is my answer for the community to benefit from:
"Sitefinity supports Sign On with third party applications. Abundant information on this can be found in this
Regarding your Thinktecture server, here is a GitHub example
I found that you may find useful"
Ivan D. Dimitrov
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Sitefinity CMS Ideas&Feedback Portal
and vote to affect the priority of the items