Mod or hack to re-enable a shop? [Minor spoilers]

[Nirual]

there are lots of shops in the game like that, sadly. Don't think there is an easy way to change that.

[skycrow]

Do you remember those items' names you missed ?

Try to add items by pressing "shift" and "~" in-game and type item xxxxxx .(There is a "space" between "item" and "xxxxx")
http://princess.kingsbountygame.com/codes.php

If you forgot those names or got nothing , maybe you can refer to the thread :
http://forum.1cpublishing.eu/showthread.php?t=35841