Actually I ment the I-Appliance BBS...or it is on codemans site...I lost a lot of my old weblinks so I can't help there.
But you pop open the cover of the one with the USB cord coming out of it. Remove 6 screws I think to separate the speaker mount from the back shell, inside you will find a circuit board, that is the stand alone USB D-A converter.
From there you do some carving to get the plugs through the back of the case...or you can cut the wires and resolder...but making room for the plugs to go through the back is the easier method IMHO.
The other speaker holds the amplifier etc, so just hook a wire back from the speaker you worked on to the untouched speaker.
If I find the link I will list it.