Yep, the chipset, the drivers, or both, are flawed. I've done everything right, tried every workaround and, like many others, no audio from the hdmi device. From this thread and other sources it's clear that Intel has known about this for months. It is to Intel's extreme discredit that they have not yet provided a fix or some sort of relief to customers that have been subjected to this foul up. I haven't even seen any official statement from Intel acknowledging the problem or offering any sort of explanation.
I'd like to be more constructive, but Intel - this is bad business.