Well, you get 0xffffffffXX, the two X'es being the two numbers you need to use. (I think). That's what I did with the error I got anyway.

Riocar 58gig (48gig + 10gig IBM travelstar) S/N : 10101747 red
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Riocar 80gig S/N : 010101580 red
Riocar 80gig (010102106) - backup