Hi lance,
I'm using MC56F8006 me too, for a project with CW 10.6 MCU eclipse and FM 1.4,
for communicating I use SCI communication with an RS232, it works fine with bean PC_master.
Another thing I notice is that I have to RESET the DSC, if not I have wrong values in FREEMASTER.
I'm sorry I haven't the USB tap to test it, but you can try to use SCI pins?
bye