How do you erase an iPad associated with an iCloud account
We have a number of institution iPads that were assigned to staff members. When a staff member leaves, we wipe the device so we can reissue it to a replacement or another member of staff.
In the past this has been no problem through Settings > General > Erase. In some scenarios we have had to do the force erase by holding down the home button and then plugging into a computer to force the recovery state and wipe it with iTunes, and that worked fine until recently.
Now, trhe device erases, but on restart we are getting messages saying that the iPad was previously associated with an iCloud account and that a password has to be entered in order to activate the device. The staff member who used the iPad is no longer employed here. So, how do we get around this? How can we wipe the iPad and not have to enter a password to their personal Apple ID? Can it be done?
FYI, I have read this: http://support.apple.com/kb/ts4515 and it does not solve the problem.
Thanks,
iPad 2, iOS 7