How Do I Create Multiple Physical Partitions/Volumes in openfiler on a Single HDD

I'm attempting to build my first iSCSI storage area network, using openfiler version 2.99 as an iSCSI target. I want to present storage to both vSphere 5 and Windows Server 2008R2 Hyper-V as datastores for my virtual machines. I'm assuming that since I'll be setting up openfiler as an iSCSI target that I need to present a different LUN each to vSphere and to Hyper-V. I'm trying to create two primary physical partitions/volumes on a single 2TB HDD in order to create two volumes/volume groups, one for vSphere and one for Hyper-V. After creating the first physical partition/volume using roughly half of the available space on the HDD I try to create a second physical partition/volume with the remaining space but the GUI does nothing and I see only the first physical partition/volume that I created. Due to the fact that my understanding of the subject is sparse (which is why I'm undertaking this) I have no idea if what I'm experiencing is due to a bug in openfiler or due to a lack of understanding on my part. If someone could chime in and point me in the right direction I'd appreciate it.

Below are screen snips illustrating the issue. The first snip is how things look before I create the first physical partition/volume and the second snip is what I see after trying to create the second physical partition/volume (after the first physical partition/volume has been created). The GUI keeps coming back showing the same thing but never creates the second physical partition/volume.

EDIT

Even though I seem to have configured openfiler to meet my objective, I didn't accomplish it by creating multiple physical partitions/volumes on the HDD. Here's how I did it:

I created a single physical partition/volume from the HDD, created a single volume group, then created two volumes in the volume group. Once that was accomplished I created two iSCSI targets and mapped a LUN to each iSCSI target for each volume, one for my vSpehere host and the other for my Hyper-V host. I've now successfully added each target as a datastore on the appropriate host.

Which begs the question: Shouldn't I be able to create multiple physical partitions/volumes on a single HDD? The openfiler tutorials that I've read describe doing this exact thing, yet I'm unable to work out how to do it.