On my new HP Envy W8 64-bit machine, MST support cannot be enabled correctly giving rise to my problem documented here: users.rcn.com/dvdbrns/mst.html.
It is clear to me the problem derives from the outdated (2006) Microsoft Generic PnP video driver ("monitor.sys") which is far to old to know how to enumerate multiple monitors hanging off a DP port running in Multi-Stream Transport (MST) mode. HP screwed up the driver configuration.
HP support claims ignorance and lack of resources, so I'm doing what they should be doing by asking here for the identification string of the latest version of the Microsoft Generic PnP WDM driver that knows how to turn on MST and enumerate 'daisy-chainaged' monitors.
It is clear such a driver exists, because Microsoft trumpets it here: http://blogs.windows.com/windows/b/extremewindows/archive/2013/07/25/pushing-the-12k-pc-gaming-boundary-at-1-5-billion-pixels-per-second.aspx
For somebody with access to AMD internal resources, it should take 30 seconds to find the answer. If posted here, I will send HP support over, and see if they can get their Product Support section to act on it. Thanks!