WE Unlimited -- Random Item Pools

In WE Unlimited, you can do something with item pools.
So I have a trigger, whenever a unit dies, it creates an item.

Create (get random item from item pool) at (position of (dying unit))

But my problem is, i don't have any items in my item pool... So:

Add item with id x to your item pool with a 10% chance to be chosen

How can I specify which items i want to add? Do I have to go set custom item value of item to x for every item? But that would not work, cuz you can only add custom value to items already placed in the map. RIGHT? o_O

I need help!
Thx

EDIT: K, I figured out that you have to press Ctrl+D in the Object Editor when viewing your items. Then it displays like 100M in front of the name, and thats what the ID is. But what i dont know is how do i write that in the Id field.

Try to enter '100M' for ID (with those quotes). It's the standard way to reference IDs and it is regarded as an Integer.
Don't use " quotes.

But it is an integer value, and it doesn't let your type in ' in the box. Do i have to do Convert string to integer?

Thats bad.
Enter some number, convert it to jass and replace the number with the '100M' code.
You can copy that line, revert the jass conversion and add a custom script command, if you want to maintain the trigger in GUI style.

How do you revert a JASS conversion? I have some maps that have a weird way of "protection" on them. I can open them in WE, but can't save them, and all the triggers are changed from GUI to JASS so I can't learn anything from them :( and I would like to be able to change them to GUI so I can learn from them.

Someone else also had problems with this so herte is the solution:

To enter the id you need the function Advanced - JASS Code (which is at the bottom), there you can enter 'idid' as the item id.

Then the percentage value is not really a percentage value. It's more the chance in relation the the whole sum of chances.
Fex. if you have 1 item with a chance of 1 it will always be dropped.
if you have 1 item with a chance of 1 and a second item with a chance of 4 then the second one will be chosen in 4 out of 5 cases.