Alright, if you need items desperately the only choise atm is to make your own custom inventory using dialogs for example. And you must come with a new way to up with a way to pick up items, maybe there's an ability that activates like WC3 Eat Tree.
EDIT: You could use something like this:
Events
- Unit is issued an order targeting an object.
Local Variables
- TargetUnit = Target of issued order <Unit>
Conditions
- Triggering Unit == MyHero
- (TargetUnit) is an (Item) == true
- IssuedOrder == Follow/Move/Attack
Actions
- *Check Inventory Space*
- *Check Item Type for carry limits*
- * "drop" item or save and hide/remove it*
- *Update inventory view*