Tax on unused leave when normal gross pay is $0?

I am processing a final pay for an employee for a resignation termination and need to pay their unused annual leave. 

I am following this guide https://www.myob.com/au/support/myob-business/payroll/processing-a-final-pay and in step 12, it asks me to enter the employees normal gross pay, however in this financial year, the employees normal gross pay is $0 as they have been on leave without pay in this financial year

Will there still be tax required on unused leave?

Note: It does not let me go to the next step with a $0 in the normal gross section

Would I therefore,

• input the normal gross from the previous financial year when they were working? 

I cannot calculate the tax on the lump sum payment of unused annual leave, due to it being a termination payment.