Add custom attributes to Assertion

[Peter Schober]

* David Huebner <david.huebner at daasi.de> [2017-09-28 12:14]:
> The requirement now is to encode some of these attributes in a rather
> specific manner, which seems to comply with SAML2-Core, e.g.:
> <saml2:Attribute Name="somename" xmlns:customattribute="somevalue"
> xmlns:anothercustomattribute="somevalue" />

I think AttributeValue elements should be used for attribute, well,
values.

Did the SP have much success with getting other SAML IDP to do that?
-peter