Payroll Advances

SUGGESTED

We have one employee who receives an advance of 1500.00 each month. I think i have it set up properly however, when I create him his actual pay cheque at the end of the month and deduct the 1500.00 from his current pay it will not automatically calculate the amount of tax, CPP and EI that it should. I have just been manually entering the taxes each month. I would like to know how to properly set this up so it automatically takes of the required amounts rather than deducting it off the advance its self as he needs the full amount not 1356.10 (deductions should be CPP -$59.81 EI-$28.20 TAX $55.89)

I know it is not working because when I select the 1500.00 to be taken off pay(it shows up as a negative)when I go under the deductions tab it does not show anything.... however, it does show the vacation on this amount.  

I am very new to the book keeping and payroll world so I hope this makes sense to someone!