Hello out there in Pro Audio land. I am trying to get two MOTU Midi Timepiece AV USBs to sync and be recognized by my MAC system as MIDI ports 1-8 (Unit A) and ports 9-16 (Unit B) I have tried following the MOTU suggestions:

Use an Apple talk cable (which I purchased) and connnect it between units A and B. Then set Unit A as ports 1-8 and Unit B as ports 9-16.
This is fine, but I cannot get the Midi set up in my MAC to recognize the second MIDI timepiece AV USB. If I connect each unit seperately to the MAC by USB cable it recognizes them, but for my purposes, MIDI routing and mixing and using input and output ports on the Unit B for MMC so my Tascam DM3200 can control certain functions in Logic Pro 7.2. My system consist of:

MAC G5 dual 2.7 gig (non intel) running OS 10.4.3 and LOGIC PRO 7.2
Two MOTU MIDI Timepiece units. Unit A connected to MAC by USB and Unit B connected to Unit A by Apple Talk cable (din cable).

Any help anyone can give me would be most appreciated because as of now, I am dead in the water, so to speak.

Thanks, Mike Knox