How can I make the workflow to use custom form

ON THE SHAREPOINT DESIGNER 2010. I am trying to create list workflow to use list content. Every list has three forms by default - edit, display and new. Forms are used to display and edit the data within the list. My search is to find solution: When I create a form that is not a default form to the list. How can I make the workflow to use this form? Workflow uses default form to create new, display or edit current item, but I need to know how non default form is being used in the workflow to edit current item.