How to Test HDD Encryption

[infosecofficer () gmail com]

Hi 
 
How can we ascertain that the encryption software we have selected is doing its jobs. 
A small test like removing the hdd of an encrypted laptop and attaching it as an external drive on another laptop shows 
the drive as unformatted. So far So Good..
 
But is there any tool available to demonstrate to the management that even the professionals cannot break in even if 
they lay their hands on the drive physically.
 
I am basically trying to make a case to push for drive encryption in our organization.
 
Please group suggest something.....
 
 
Best Regards
 
Samir