Class method inside the custom task in SAP workflow

Hi Experts,

I am new in SAP business workflow. I have created a workflow. The first step is user decision step : approve or reject. I have used rule in this step to determine the agent. If agent will approve, then my next step is an  activity step. In this step, I have created a custom task. Inside task I want to use one class method. I have create the class and method. How to use the class method in the task? How to instantiate the class when I will use in task?

Thanks & Regards,

Arindam Samanta.