Neutral Building - Add Item-Type to Marketplace Help

Hello. I'm making an epic Co-op zombie map (491 Triggers thus far), and even though it's late into development, I decided to add a new element. I want to have Health units that the players can find at rest stops and use them to replenish their health (Ã* la Half-Life 2). Each health unit will have a limited stock of 10 charges (free items), each that restore 250 health. My problem, however, is that when I have:

Events:
Time - Elapsed game time is 1.00 seconds
Actions:
Unit Group - Pick every unit in (Units of type Health Unit) and do (Actions)
Loop - Actions
Neutral Building - Add Health to (Picked unit) with 10 in stock and a max stock of 10

...then it glitches up. When I have a player take one item, the item disappears from the shop! I tried it with other items that aren't automatically used when acquired. For instance, when i gave it 10 clips of ammo, it did the same thing. Gave me one and threw the other nine into the abyss.

I was thinking about pulling together some system involving custom values, etc, but I'd like to do it as simply as possible. Any help? Thanks!

I've actually been working on the same problem myself. I have no trouble adding units to stock, but items have the same effect as you explained. I'll let you know what I figure out, when I do.

Okay, set the value of the item-type to the number of stock you want, whenever a unit purchases a item, set the value to (value-1) and add the item again, if the items value is 0 dont add.
If you want to add stock after a certain amount of time (like it does normally), create a periodic trigger for each item that sets its value +1.

Is that just a workaround for another problem though? It seems unnecessary, but maybe I'm wrong. Isn't there a setting or ability maybe that the shop needs to have to keep it from doing that?

I used Tidehunter's method (as was my original idea) and it worked fine. But one would think there'd be an easier way to do this. Thanks for the help, guys.

Give your shop to Neutral Extra.

Optionally with some alliance changes so he's actually neutral, don't want a red mouse cursor on a shop...

Marketplaces automagically sell an item only once, theres no way around this.