OS X, Parallels, and DisplayLink with 3rd monitor

I recently purchased a Sewell USB-to-DVI adapter with a Displaylink 165 (DL-165) chipset so I could setup a 3rd monitor on my 27", Late 2009 iMac. I am running OS X Lion 10.7.4 and in Parallels I have Windows 7 Enterprise 64-bit. The second monitor is connected via mini-DVi.

Whenever I step away from my machine, I hit a hot corner to put the display to sleep and lock the computer. Subsequently, all displays go black, and the two add-on monitors go to sleep. When I return, I enter a password and the displays should come back up.

The display connected via mini-DVI comes up as expected, but the one connected via the Displaylink device does not. I have been troubleshooting this with a technician at Plugable.com and have discovered the issue isn't with the Displaylink device, which works just fine on OS X. Rather, the problem is with Windows 7 running in Parallels.

When I return to my computer and exit sleep mode, the monitor connected via USB stays black. If I exit Parallels, or use Parallels to suspend the VM, the monitor connected via USB comes back on. Using Windows to put the machine (within the VM) to sleep does not resolve the issue, but shutting down Windows does. Restarting the computer also resolves the issue.

So, it appears that something about how Parallels intercepts USB, despite the fact that the display adapter is not configured to connect to the Windows machine (and in fact is configured to always connect to OS X), breaks this USB-to-DVI connection. My workaround solution right now is to use Parallels to exit coherence mode, suspend my Windows 7 VM, resume it, and then re-enter coherence mode, which fixes the display issue, but this obviously is not ideal. And as a sidenote, I have tested this in full screen mode as well--the effect is the same. I have also upgraded to the latest version of Parallels and have the latest version of Parallels Tools installed on the VM.

Any suggestions would be greatly appreciated.