I'm a tad confused whether you want to use the MBP with the lid closed or make it go to sleep.
Read through this Apple TIL and see if it helps:
http://support.apple.com/kb/ht3131Well this is how it is SUPPOSE to work, however it does not. I have attempted it with both a USB mouse and the Bluetooth Kbd and Trackpad.
Putting it to sleep from the "drop down" works, however it will not wake up from the Mouse nor the Bluetooth, once again the lid has to be raised.
I have not yet been able to operate with the lid down.
Daryl