If your drive does not show in Workbench to format, open a cli window and try formatting it there.
I believe the command should be Format [device] [diskname] [options]. Device shopuld be the device name of your new mhard disk as shown in HDToolbox. Diskname should be what you ae naming it. Options include such things as International mode, etc that you can normally select from the workbench.
Using the format command from a cli you should be able to format your disks and they will appear in the workbench.
//RC//
