I can easily associate Thinktecture Authorization Server with Identity Server. Is there a way to associate Authorization Server as a relying party to an Identity Provider that only deals in SAML and not WS-*?
Authorization Server uses WIF and WIF doesn't support SAML.
Neither does identityServer.
You could go the route:
Authorization Server --> WS Fed --> ADFS --> SAML --> SAML IDP
or add a SAML stack to Authorization Server. This is non-trivial!