Solved: Getting error trying to create VMDK Pass-through (RDM) on ESXi 6

I'm trying to create an RDM passthrough VMDK file with vmkfstools via Putty (SSH) on a brand new ESXi 6 install. There are two datastores attached the new ESXi host. The one that I'm trying to get this VMDK created on is active and already hosting the vCenter appliance.

Here is the syntax of what I'm getting. I zeroed out the SN's and some other information:

login as: root
Using keyboard-interactive authentication.
Password:
The time and date of this login have been sent to the system logs.

VMware offers supported, powerful system administration tools. Please see www.vmware.com/go/sysadmintools for details.

The ESXi Shell can be disabled by an administrative user. See the vSphere Security documentation for more information.

[root@esxisuper:~] vmkfstools -z /vmfs/devices/disks/t10.ATA_____Samsung_SSD_850_EVO_1TB_________________XXXXXXXXXXXXX /vmfs/volumes/SSD_Sam950ProNVME_500GB/ET03PT/ET03PT.vmdk

Failed to create virtual disk: The specified device is not a valid physical disk device (20).

I know the directory (/vmfs/volumes/SSD_Sam950ProNVME_500GB/ET03PT/) in which I am trying to create the VMDK exists as I created a VM (with no HD) from vCenter (web client) with no issues. The VMX and VMSD are both present in that directory. The device ID for the HD I'm trying to use all looks correct and there are no errors on that side of things. There is already a Win10 install on that HD that I'm trying to passthrough.

Let me know if I should provide any more information. I'm just not sure what I'm missing here.

Thanks in advance for your help!