add shipped option to order manager

Hi, I desperately need to be able to mark my order status as shipped in the order manager in shopperpress. I still find it hard to believe that a shopping cart designed to sell physical products doesn’t give the admin the option to mark an item as shipped. Does anyone know how to add another option into the drop down menu to be able to mark an order as shipped or to maybe add another column labeled “Shipped?” and a simple check box to show the shipped status. i would be really grateful if someone could help me as I have spent ages setting up the site and I don’t want to have to change to another shopping cart for a problem that I am sure is easily sorted by someone with the right know how. Many thanks in advance.