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Set the AttributeSourceIds value to which newly resolved attributes you would treat as the real username. This is probably the same or a subset of AttributesToResolve.
Review c14n/subject-c14n.xml and ensure the PostLoginSubjectCanonicalizationFlow bean has been uncommented.
At this point you should have a valid locally understood username to pass into the "normal" resolver that already works, which is now available from places like:
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