I've moved this thread to MV Support. Please be sure to post your threads in the correct forum next time. Thank you.
You need to give us more information. Are you sure it's the Inventory (Items) screen where it's not appearing, or is it actually the equip screen? If you have the shop set up to buy these things, and you do successfully buy them, then they should appear in your inventory/items. Whether they appear in the Equip screen depends on whether you've added the appropriate trait to the actor or class to allow them to equip it.
If you can't get it working, please provide screenshots of the armor item from the Armors tab, and the event page with the Shop command showing that armor item for sale. Also state whether you have any plugins added to your game, and whether disabling ALL the plugins makes a difference.