Eric, thanks for teh answre and link. Actually we want to use QuickSync without any display connected, i.e. in a headless mode, just streaming data in over network, transcoding it and streaming it out over network again. So, we neither have a display attached to the intel GPU nor do we have a secondary GPU.
The last post in the above link shows how to enable QuickSync when the Intel GPU isn't connected.
For HW acceleration work (DXVA), a screen must be connected to the GPU that creates the device. This is a DirectX9 limitation.
What you can do is connect a screen to one port and extend the desptop to another, later remove the actual connection. The trick is to keep the disconnected screen a part of the desktop so DirectX will enumurate it.
Annoying? Yes. But drivers must comply with the OS requirements.