I'm not suggesting that he go behind their back; he should definitely inform them of his intentions, but trying to work through them isn't the best course of action. In the end, using the news site as an intermediary might just piss them off.
They placed themselves in the middle and it's ultimately their client, trying to deal with them first as outlined above is the way to go- they created the misunderstanding, they should get first crack at fixing it.
Paul