General Ledger account masks in Microsoft Dynamics GP are set up to change a department, and the distribute works correctly for all paycodes except the Vacation type paycode.
The vacation dollars are distributed when the vacation amounts are accrued*. They are not distributed when they are paid out. Therefore, there is no functionality to track this when they are paid out, as you do not want it distributed twice.
*On the accrual, only the debit is distributed. The credit books to the Vacation Payable Account that is set in the Payroll Control Accounts-Canada window and is not distributed. By design, this field only allows one account.