You can Use the drive tools that came with the drive, or downloaded from their site.
I haven't used Vista since RC1, but I'm almost positive you can manually set the partition size to install on.
I saw this on the linked MS help page.
Note If you are installing Windows Vista on a new hard disk, the Setup program automatically creates an active partition.
So you might need to use the HD manufacturers tools.You cannot select or format a hard disk partition when you try to install Windows Vista