Backdated Terminations affecting T&L RP status

Does anyone have steps to resolve backdated terminations? We have paid an employee past his termination date by 1 month. HR has entered a backdated termination affecting 3 pay periods. T&L is re-processing the time as RP. We do want the time to have an offset but at ES status so that we can process the negative time to collect from the employee's leave banks.

We cannot inactivate the workgroup, as time exists past the date. I have tried changing his workgroup a number of different ways, as well as Assign Schedule but I cannot seem to generate offset ES time. I have also pulled the termination row and tried the same changes to workgroup and schedule but this didn't work.