Scoped attribute not passing SP filter

[Joep Driesen]

> Turn the IdP's (or the SP's, since you seem to control both?) logging
> up to DEBUG and look at the actual XML representation of the attribute.
> (Or disable encryption, then you can grab it from the browser in
> transit, e.g. using Olav's SAML tracer plugin for Firefox).
> 
> Any PHP at the SP won't give you additional info compared to the SP's
> log files.
> Also the SP's Session handler at /Shibboleth.sso/Session already has
> all that info readily available in your browser (other than that the
> same as above applies here, of course).
> -peter

I only directly control the SP, though I am in constant contact with the IdPs administrator.
We already looked at the IdP logs and the result was:

<saml2:Attribute FriendlyName="NewAttribute" Name="urn:mace:kuleuven.be:dir:attribute-def:NewAttribute" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
         <saml2:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">000000000 at kuleuven.be</saml2:AttributeValue>
</saml2:Attribute>

It looks exactly the same as the other scoped attributes in the log, which do work:

<saml2:Attribute FriendlyName="eduPersonPrincipalName" Name="urn:oid:1.3.6.1.4.1.5923.1.1.1.6" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
         <saml2:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">00000000000000000 at otherscope</saml2:AttributeValue>
</saml2:Attribute>

I'm not quite sure which class I should set to DEBUG on the SP side. If already tried 

log4j.category.Shibboleth.AttributeFilter=DEBUG
and
log4j.category.OpenSAML.MessageDecoder=DEBUG

but neither made the value of the NewAttribute show up in the logs.

Joep