CS-Cart - Invoice number start from 1 each year

Need an add-on that will change: invoice numbers like: {invoice number}{year} invoice number should start from 1 each year. We want a full manual how to change it in CS-CART so we can do it by our selves. So you have to give instructions like : - open file with filename "filename" - Search for text "text-code" - Replace by text : "new text-code" Also MySQL changes must be in manual.