How to create a standard earning element that pays at 1.5 times the hourly rate

Summary: We have a need to pay hourly employees at a rate of 1.5 times when they are called in to work while on call.

Content (required): We are creating a new standard earnings element for hourly paid employees with a Secondary Classification of Regular and the Category as Time Card. The element should pay at 1.5 times the hourly rate. On the earnings results, under Input Values - Multiple, the default value has been set to 1.5 but when we run payroll, the element is only paying at the regular rate of pay.

What is the best way to create a new standard earnings element for hourly employees that will pay at 1.5 times the regular rate of pay?