I contacted HP last night, and after a significant run-around was forwarded a private link to download the March ISO. Unfortunately, Update Manager (which I intend to use) immediately flags it as non-compliant. I've updated the HP case with this info, but have yet to hear anything back. They seemed quite surprised by the issue, even after being pointed to this thread and the associated KB article.
guessing this isn't the response that you wanted, but hate to see anyone else go through the HP support pains I did to receive a file that doesn't work.