need help setting up a lexicon mx200 in logic

i just went out a got a lexicon mx200 http://www.lexiconpro.com/mx200/index.asp

now this can used as a normal hardware fx processor and an AU plugin via usb.

the thing i didn't realize is that to use the plugin ,not only does the usb have to be connected but the manual say i need to connect the audio as well,they recommend using the S/PDIF Digital Input / Output on the unit,which is no problem since i can send those to the S/PDIF in and out on my tascam fw1082.

my question is though how do i set it up in my environment so that it work, the usb is working fine and when i turn a know on the hardware unit the same know will turn on the gui.

thanks for any help in advance