Need to create a virtual disk from a usb thumb drive that has no os

I am in need of the following:

1. Create a VM with Windows 7 (done)

2. Create a virtual disk of a usb drive or an e01 image of the usb drive

3. import the virtual disk into the Win7 VM as the 2nd drive

You would think this would be easy and I have found out that this is not.   Anyone have any suggestions for converting a usb drive to a virtual disk.  Disk to vhd will not work!