Hi Sandico,
You can enable them as follows:
1. Create a business role UNLOCK_ME with some simple permission.
2. Using the Data Migration tools, assign this business role to all the business users you want to unlock.
3. In the Business User screen, use advanced search to filter on users with business role UNLOCK_ME.
4. Select all filtered users and click Unlock User.
5. When all users are unlocked, use Actions|Deassign Business Role to remove the business role from the users.
6. Remove the business role UNLOCK_ME (unless you want to do this again at a later date.
Ron