As mentioned earlier check the parameters for payslip to bring the arrears on payslip, For your reference check the below image where similar case employee is joined in the month of January and payroll is executed in the month of Feb with arrears same wage types will appear on payslip this is standard functionality of SAP you can find out in the image with * with out * * indicates arrears.
let assume your basic pay is XXXX when arrears are there then another line appears with *XXXX indicates arrears similar to your case joined in the month of January and payroll executed in the month of February then one month arrears appear on payslip like above for each wage type.
This is completely integrated with payslip design and PC00_M40_CEDT parameters which we are using for Remuneration statement variant.
I hope you understand.
Regards
Venkatesh