Not sure if this was intended or if it is a small bug. I don't want to be ignorant, so I'll stay neutral. Okay, so the suspected bug: (How to reproduce) When you create a post in "Buying, selling or trading" then edit that post, when you hit "save" your iTrader information disappears. I am using Google Chrome. Not a huge bug. But just letting you know it is there. Cheers.
Yeah... it's because that post isn't running through the normal hook system because the HTML for it is being rendered and output in AJAX when you edit the post. Not really a huge priority to fix since it's only when you edit.