Rainbowduino & Common Cathode LED's

Ok…I have been searching the far corners of the internet to find a project using a rainbowduino and common cathode RGB led’s…I know the rainbowduino uses a constant current sink LED driver…

I am trying to figure how I need to wire the LED’s off of the rainbowduino’s red, green and blue pins in order to create my own 4x4 or 8x8 matrix. I am a bit confused on how to create my own grid…
Also, since I only have common Cathode RGB LED’s, what do I need to change to make this work? Any help would be greatly appreciated!

Maybe you can refer to this.