How do I run a physical windows partition in a VM?

I'm using VMware Fusion 5.0.2 on OS X 10.8.2

I created a VM that lets me run Windows 7 booted from a partition on a physical external disk (attahed via USB 3.0). This works (as long as the disk is connected).

Now I want to do this again with another windows disk.

On 2012-02-20 I followed instructions to do this. I recall that Fusion asked me at one point early in the process if I wanted to boot the VM from the physical partition or if I wanted to make a virtual disk copy of the partition and boot from that.

Problem is, I can't find the instructions again, and I can't find anything in the VMware Fusion user interface that leads to this outcome. I've tried googling using any and all of the words above. Can't find it. Where are those instructions? How did I do this?

Note: this question has absolutely nothing to do with Boot Camp.