Where to put the amazon buy buton

Hi. The amazon buy button not working in the classified theme. The Short code [AMAZON_BUYBTTN] would go into the Listing page Layout/custom layout, but the custom layout screws up the single listing page completely, because it gives a different look compare to the way it’s already setup.
Where would I be able to put the shortcode in the wlt_amazon.php file? Anyone have any idea? This buy button should have been solved a long time ago in the classified theme. As I see it many people are complaining about how sloppy is it.
Thanx a lot if anyone have the answer.