MAc Users...please help

I am in the Midi setup of my Mac...In this setup, I have my firewire 410 icon connected to my ensoniq asr-10 icon and my Akai mpc 2000xl icon I created. The IAC driver icon is appearing shadow like and not highlighted and I cannot click on it. I am assuming this is the mac sound card? Does anyone know how i can set this up?

IAC is for virtually connecting midi applications, within the computer

OK, Thats what I thought...but should I be able to virtually connect the IAC driver icon to my firewire 410 icon or other midi icons...and if so could you elaborate on how I do that...