prlctl With Multiple Physical Partitions

When I configure my VM via the GUI, and I add 2 physical partitions on a disk, and then list it via "prlctl list --info" hdd1 is shown as follows:
hdd1 (+) ide:1 real='WDC WD2500BEVE-00WZT0 (disk1)' device=</dev/disk1s1 /dev/disk1s6>

But if I delete the hdd, and I try:
prlctl set "XP1" --device-add hdd --device "</dev/disk1s1 /dev/disk1s6>" --iface scsi --position 1:0

it rejects it with the message: Unknown device: </dev/disk1s1 /dev/disk1s6>. I also tried using "/dev/disk1s1 /dev/disk1s6" for the device, and that received a similar message.

How can I add multiple physical partitions from the same drive using prlctl?
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Parallels Desktop 6 for Mac, Build 6.0.11826