Disk utility won't let me use the restore option to get a .dmg image onto a USB
I would suggest using dd, from the command line (Terminal).

The syntax is as follows:

sudo dd if=/path/to/file/&lt;file&gt; of=/dev/disk&lt;your drive number&gt; bs=1m

It will prompt you for your password, and you will not be able to see it as you type.

To get your disk number, you can run diskutil list from Terminal, and find the disk that most closely matches your drive's stats.