Issues when viewing opencart site within Facebook app

Hi

I've got a client who posts their products from their opencart store onto Facebook (their business page). When you view this post within a Facebook app (in this case the iPhone app), it takes you to the page (which views OK), but some of the buttons don't work as they should... in particular the Add to Cart and quantity selector, making it a bit of an issue.

Clicking on the open in Safari button, so that you are viewing the page in iOS Safari works great.

My question is, should it work within the Facebook app as it should in iOS Safari? Or is it not possible due to being a browser view inside an app. I thought I would ask the question first before trying to tweak some code.

If it should be possible and anyone has some tips to try, that would be great.

Thanks
Wayne