FireWire External Drive & FireWire DV Camera

Hi

How do I connect a FireWire external drive and a FireWire digital camera to capture and save digital footage in Final Cut Pro 5?

My external drive (Hitachi 500GB in Impact TB-3502 enclosure kit) is equally partitioned into 2 partitions as HD2A and HD2B. I try to save FCP Media in HD2A and FCP Projects in the internal system drive (Macintosh HD).

When I connect the external HD with FireWire800 and the digital camera with 6-pin FireWire400 to the MBP, I get file I/O error !

When I connect the external HD with USB2 and the digital camera with 6-pin FireWire400 to the MBP, it seems ok ; digitized file is saved in HD2A. But this would be a slower option, I think.

Is there a better option (to use FW800 and FW400)?

Thanks.