Proxy IdP hybrid question local and remote IdPs

[Mak, Steve]

Is there documentation on how to take a proxy attribute and turn it into a Subject NameID?

I need to take employeeNumber attribute value and put it into the Subject NameID.

I know how to do that normally, but I can't get this to work:

    <AttributeDefinition id="proxied-subject" xsi:type="SubjectDerivedAttribute"
        forCanonicalization="true"
        principalAttributeName="employeeNumber"
        />

    <bean parent="shibboleth.SAML2AttributeSourcedGenerator"
        p:omitQualifiers="true"
        p:format="urn:oasis:names:tc:SAML:2.0:nameid-format:persistent"
        p:attributeSourceIds="#{ { 'proxied-subject' } }">
    </bean>

INFO [net.shibboleth.idp.saml.nameid.impl.AttributeSourcedSAML2NameIDGenerator:221] - Attribute sources [proxied-subject] did not produce a usable identifier