Interesting...the auction and the BIN page is the same on mine but you say that the box is not checked. I pressed the BIN on 4 of your items and all of them immediately took me over to the checkout page to pay for the items. Usually that only happens when sellers have the immediate payment required checked on their listings. When you hit BIN on my listings, it goes to a screen that says "commit to buy" and when I do this, the item will appear on their purchase history page under items awaiting payment.
Another way that we can do this is to tell your customer to put the items in her cart and when she is done purchasing from you, go to her cart and press "request total" at the top right hand side of your items.
See pic:
