I just noticed that the UCS@school documentation is only available in German. Too bad.
You should really take a look at the general UCS admin documentation, though, especially the sections about [url=http://docs.software-univention.de/manual-4.1.html#domaenenkonzept]»Domain Services/LDAP Management« and its sub-section about the »SAML identity provider«.
I don't know which features Univention is thinking about exactly when they talk about identity management. Maybe after reading the aforementioned sections you could ask a couple of questions about the support status of various features or how certain things are done in a UCS setting. That would be easier to answer.