Hi,
Auctiva DOES offer those changes. You must have originally listed through Auctiva, right? That was before Auctiva made the changes, they're quite recent. So by relisting through Ebay, your listing stayed as it originally was.
Now when you do a new listing you will see these changes in 'item specifics'. To tell the truth, I think it's a pain...LOL. I use as few item specifics as possible, it doesn't seem to make any difference in my sales