To get ASIO to work in MC on the Audigy (or any internal Creative sound card for that matter), you need to have MC upsample the output to 48 kHz. You do in the "Output Format" plug-in in the "DSP Studio" dialog box.
Since you are using an Audigy, I recommend letting the card's drivers do the 2 channel to 5.1 channel converstion. (Do this in the "Speaker Settings" control box.)
Also, be sure to download today's build first (v.9.1.302) as they just fixed a problem I was having with ASIO output on my Audigy 2 card.
A very simplistic overview:
Waveout -- kmixer (an internal Windows driver) processes the signal before sending it to the soundcard
DirectX -- DirectX processes the signal before sending it to the soundcard (and still possibly sends it to kmixer first)
ASIO -- bypasses both of the above sends the signal straight to the hardware
The Audigy expects a 48 kHz signal, hence why if you use ASIO, you need to upsample it first. (Those 3rd party drivers mentioned above with do this for you.)
Omni