You would have to make a new shop.
A map location with shelves and counters covered in item graphics that call up a "This is a X, and it costs X, would you like to buy it?" dialogue that checks the player's current inventory space would work.
Or a main location with a picture of your items all laid out with event links on each item that pull up a similiar dialogue.
For selling, I think you can set up a shop location with no items for the player to switch to his inventory and sell whatever he wants to sell.
Maybe also include a guy who asks if you would like to refill your ammo. Then check how much more ammo you can carry and quote a price.
We've been trying to restrict inventory space too, you see. It's kind of a pain.
myshkyn
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"I'll give the fans just what they want, and nothing else at all."