Payment terms on Payment methods

Hello there:)
Can you please help to find me out how to fix this:
I have set a demo shop on localhost and marked it as in production. I’m planning to open a shop just always lack of time. This time i think i made little bit more then all last times:) So here is my story.I made all the neccesary translations for the front end and PDF invoice, configured payment methods, shipint methods, cost rules and etc. All goes ok i can make an order, i recieve a notification but there is one tiny problem for the very begining. A new customer will have the only way to choose the payment method - cash on delivery. I set it up and chose this method on my order. When I print PDF invoice in the backed i see that the order was made 2011-07-25. But in the end of invoice file i see saying. Pay till 2011.08.01. This means the shop somehow counted a week for paying cash on delivery that makes no sense? Can you please help me how to control this part? I look towards future. For example some of my customers i would like to have 30 days delay of payment after the order is made using payment method Invoice.