Need to have Employee Number history

Summary:

We're loading active employees and ex-employees with HDL. The customer requires to keep the track of the employee number changes in the past. We've tried to enter each person number change under "person legislative data" region but it did not work. Later on we've discovered that the system cannot record the history of the employee number changes done in the UI. Is there any way to have the history of this information on the employee record?