How set a timelimit to post pay a order

-- url of the page with the problem -- : mywebsite.com/mypage
-- HikaShop version -- : 2.2.2
-- Joomla version -- : 3.1.5
-- PHP version -- : x.x.x
-- Browser(s) name and version -- : XXXXX x.x.x
-- Error-message(debug-mod must be tuned on) -- : Error_message

In my Orders View i can display a button to pay later but how i can set a time limit for the customer can pay
example i have a product in stock for only 2 days i need be able set he can pay only 2 days after this the order should be canceld automatic.