I might just work on getting DirectSound working, and the get winmm to use direct sound instead of winmm using the sound card directly.
You can use Microsoft's dsound.dll in native mode and it will use wine's winmm drivers.
I'm pretty sure that's the wrong way around. DirectSound is implemented on top of WinMM for a reason: I'm pretty sure that's how it's done in Windows and anyway, we don't want to duplicate drivers.
We need to get to a single API between sound hardware and windows apis.
Yes, that is WinMM