Refund Clients

There needs to be a capability to show refunds on invoices for individual items per product. For example, if you invoice $5 for shipping on that item and you ned to refund $1 for shipping and then that affects the tax amount and the mark up amount. There needs to be a way to break down each product into individual lines when refunding so the client can see where the refund is coming from, the product or shipping or tax etc. Thanks