The mapping of kernel streaming WDM audio devices to waveOut, waveIn and mixer devices appears to be quite different to previous versions of Windows, and is causing problems with multichannel sound cards. Each output pin seems to map to a waveOut device named only by the pin type (for example "Speakers"), each input pin on each input miniport seems to map to a waveIn device, again named only by the pin type, and all the topology miniports created by a multichannel card are lumped into a single mixer device. This is going to cause great difficulty for application software that needs to be able to find its way around the various outputs, inputs and mixer controls on a multichannel card, particularly if that application has to work on both 2000/XP and Vista. To make it even harder, none of these changes are documented in the Vista Beta 1 WDK.

Is there any way under Vista to distinguish between pins of the same type (say "Line In") on a multichannel card, or multiple instances of the same card?
Is there any way to force Vista to use an XP-compatible mapping (ie. input, output and topology miniports correspond one-to-one with waveOut, waveIn and mixer devices)?

Is this new behaviour going to be documented in the near future?