If the HDD was formatted with a disk utility other than Apple's own it may be unapproachable with HD Setup. At the very least you should get a message that 'This disk is unreadable ...', and be invited to eject or initialize it. That you do not get (or report) such a message indicates that you will need a larger hammer for the job: Silverlining (LaCie), FWB ToolKit, Intech's SpeedTools or ATTO's utility (the name of which escapes me for the moment). Silverlining comes free with LaCie's external drives. The current (and last for OS 9) is v6.5.8. FWB's, InTech's and ATTO's software comes at a price. All of these utilities can install the logical partitions on your drive (if they test it as functional) in accord with Apple's protocols, and install a driver as well. Only if the present driver/formatter was from way out left will the quoted utilities not be able to 'take over' the drive.

There are freeware/shareware utilities also, for which you can Google.

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(60x) 13DT + 3PB + PTPro; (G3) 7DT/MT; (G4) 3T + PB. System 8.1 to OS 10.5.8