Thanks for all the info guys.
I accomplished my goal by installing a Lite-on DVD burner out of one of my servers into the enclosere. This enclosure worked fine with the the Lite-on for copying some files off other machines, and I ended up not needing the DL capacity in the interum.
So the BenQ 1620 found a home in the server/workstation that lost the light-on drive.
The whole idea was to have the capability of passing large amounts of data, backing up, or passing movies, etc.
So an external enclosure that actually functions with the 1620 Pro, was the objective.
Based on this thread I have gathered that the ALI chipset does not allow full functionality with this drive.
and based on this comment:
"The Prolific PL-3507 is both Firewire & USB2. The Firewire half can run up to 16X with a BenQ 1620, but only if you run the external Firmware 47L9"
It seems I know what to search for, enclosures with this chipset.
So now the objective is to confirm which enclosures offer the compatible chipset "Prolific PL-3507".
If I have difficulty finding this information, I guess I will start a new thread.
But thanks for any further insight and information!