I got a Delta 66, and thought I would need to still have a regular system soundcard. Someone had told me the outs 1 and 2 support directsound...it didnt hit me at the time, but now I realize that the Delta 66 works with all my games and system sounds....wavs, avi's, etc.....The only things I dont have are cd audio and an internal synth. But, I use an external tone module for MIDI and as far as cd audio, I could easily make a cable and route it into the Delta 66 if I wanted to.
My point is you may be able to do the same with your mona. That could possibly save you a LOT of headaches. Do you know if any of the Mona's outputs support directsound?
If you do set up a second soundcard, I know it's possible, but it probably wont be easy. You'll may have to try a few different things before you find what works.
Good luck!