I live on a MS free island and cannot say much about MS integration. As author of dm.saml2 and dm.zope.saml2, I can say provide some general information.
My "saml2" modules are based on PyXB. This is a subframework for XML-Schema handling (a standard, SAML2 heavily depends upon). It can create a Python class for an XML-Schema (called a binding) and then parse a schema compliant XML document into an instance of this class or serialize such an instance into a schema compliant XML document. In order for the parsing to work, PyXB must have a type binding (i.e. the corresponding Python class) for each XML-schema referenced by the XML document.
In your case, the metadata XML document apparently references an XML-Namespace for which PyXB does not yet have a corresponding Python class (i.e. the corresponding type binding).
dm.saml2 (in fact PyXB) comes with the type bindings typically used by (pure) SAML2. It knows nothing about MS specific extensions, however. It is not difficult to use PyXB to generate new type bindings and make them available for later parsing. Dylan has done this in collective.saml2 to get ADFS support. I cannot tell you why it does not work in your case: maybe, you are not using collective.saml2; maybe, you missed some installation step for it; maybe, your ADFS version uses another XML-schema (not yet handled by collective.saml2).