Vacation accrual tracking and maximum

We are setting up vacation pay to be paid out on each paycheck.  It is the start of the year and no one has used any vacation yet.  We are using Quickbooks Desktop Enterprise Contractor edition.  I've gone in to the Employee Center and for each employee gone into their "Payroll Info" tab and under the "Vacation Pay" button, selected "Pay every period" and defined either 4% or 6% depending on the employee's years of service.  I've then checked the individual Payroll Items that accrue vacation from the list.  However, our company does not have paid sick leave and employees can take time off without pay that will effect the total hours they work in a year.  We want to be sure that each employee is receiving the right total amount of vacation pay in the year that equals either 2 or 3 weeks wages.   Can we define the maximum vacation hrs to be accrued per employee?  And is there a way to divide that per paycheck instead of a % on the hours they actually work? 

Thanks!!

Some of the help articles reference Vacation/Sick Policies and that seems like the function we need, but we do not have that option in our Payroll & Employees-Company Preferences screen.