MBP 15" i7 OS X 10.6.7 DisplayLink 1.6b3 DL-195- clam shell not working
 

Hello everyone, I need some assistance

Here is my setup:
Macbook Pro 15" i7 (early 2011 w/ Thunderbolt) running OS X 10.6.7
DisplayLink 1.6b3
Plugable 10 port USB 2.0 Hub (w/ power supply)
Two (2) Plugable UGA-2K-A (DL-195)
Two (2) Dell P2210 LCD monitors

MBP and Plugable UGA-2K-As connect to Plugable USB Hub, each Plugable UGA-2K-A connect to monitors via DVI.

Problem
I can't get my MBP to work in "clam shell" mode. As soon as I close the MBP lid, the LCD monitors go blank and my MBP goes to sleep. I tried restarting the MBP and closing the lid as soon as it booted but the monitors were just blank. If I open the MBP lid, the monitors work fine.
I have the same exact issue with the UGA-2K-As plugged directly into my MBP (no USB hub).

Am I doing something wrong or is there an issue with running in "clam shell" mode? Thanks in advance.

To make clamshell mode work on Mac you need to have one monitor connected to the built-in video output port. I have memories of an external keyboard required as well but not sure that is still required.
Anyway, Mac OS won't stay awake with just USB monitors connected. Which is annoying as we all know that having just one cable to connect all peripherals is so convenient.

Thanks for the response. I've replaced one of the DisplayLink adapters with a Mini Display Port adapter to DVI connector. One monitor plugs into the MDP-DVI and the other monitor plugs into the DisplayLink adapter. I'm using a bluetooth keyboard and mouse (non usb). Other than this snag, the DisplayLink adapter works fine, just wish I'd known this before spending a Saturday trying to figure out why this didn't work. BTW, the support staff at Plugable (the DisplayLink adapter I'm using) are great. They responded to my email about this pretty fast. Not sure if this issue is posted somewhere in the FAQ or the "list of things customers would expect to work but don't work on OS X" document but adding issue to it might help future customers. Thanks again.

You can install a small free mac program called Caffeine and it will prevent your Macbook from going to sleep ever. It will put a little coffee cup icon up by your clock. Click it so the cup look full and your mac will not sleep. If you want it to use the energy saver or scheduled sleep settings, just click the cup again so it looks empty.