If the drive has two firewire ports, connect the camera to one FW port on the back of the drive and connect the drive to the computer using the other port.
If the drive does not have two firewire ports, you'll need an Expresscard 34 firewire card to create a second firewire bus. The card goes in the slot on the side of the computer. Hook up either the camera or the drive to it.
The cards can be found online for a reasonable sum of money.
Do not use USB.
Good luck.
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