As far as I recall you should be able to see the HD as a NDOS disk on your system... I'm though not sure if WB2.05 is cabable of showing this...
But You'll only need the HDToolBox from Your workbench disks to do do the job... But You'll have to format (NOT LOWLEVEL FORMAT!) the disk first and then partion it afterwards... In many cases it's enough to do a quickformat on the drive...
Hope it helps.. And welcome to Amiga.org