Hey,
I checked the page from soundblaster sound cards and I can't find any product there which is MAC compactible. They all developed for Windows platforms.
I also checked a forum for mac users (
http://forums.macrumors.com/showthread.php?t=88352) and there they talk about this problem. You can only load the default drivers but these are not helpful because you can't control anything from the channels (like volume and so on).
So you need an alternative soundcard or you have to install Windows via Bootcamp at your mac.
Sorry that I have no better answer for your question. maybe someone knows a solution but otherwise these are the only options you have.
regards
Christian