Hi,
While doing retro for arrears, it will give at a time in one payroll only, no standard for installment payments.
2nd option:
Calculate the Total Arrears amount and divide it by four installments and through IT 0014 with New wage type and give for 4 months as start and end date.
* you have to create a new wage type which is taxable and assigned to IT 0014.
* add this new wt in Remuneration form in Earnings side.
Regards,
Praneeth kumar