Pass through storage controller question

Hi,

I have built a desktop PC which runs ESXi 5.5 booting off USB stick and all I/O hardware is recognised.

I want to run NAS software on a VM and have it directly control the hard disks in the PC, so I have successfully passed through the on motherboard storage controller in preparation for building this VM.

Am I correct in thinking that since the storage controller can no longer be used to create datastores, and because this is not possible on the boot USB stick, do I have to install another storage controller and attach disks in order to build this VM?

Thanks.