Ixiepixigirl to sell wall mounted items in the B&H pack you need the Ingenious Ingvar Creator's Showcase from the build/buy catalogue under Surfaces>Misc. It's a large floor mounted board that holds several items at a time. Like the Ingenious Ingvar pedestals it allows you to display items for sale and the description says "this allows Sims to sell wall hanging crafts and collectibles as part of a small business". I've only used mine in retail lots so far and so I haven't tested it yet for a small business but based on the description it should work.
So far my biggest criticism of the new pack is that my pottery items keep breaking very quickly without any interactions from Sims. If they're not given an unbreakable glaze then I end up with little piles of broken pottery all over and with the wall items it looks really odd to suddenly have the broken pottery sticking out of the wall. My current Sim isn't doing the pottery skill but she's going to have to learn it in order to make her full set of the Contemporary design pottery items unbreakable to stop this from happening again. For now she just has an inventory full of the broken pieces. They'd only been displayed a couple of Sim days 😞.