When creating a new event and spawning one or more items, the lifetime of the event takes priority over the lifetime of the item. As a result, once the lifetime of the event expires, the item(s) in question will despawn, even if the item is deployable, has been deployed, and is in-use.
In testing on a vanilla server with no other changes to the XML configuration, other than to drop 1x "LargeTent" and 1x "CarTent", both the "LargeTent" and "CarTent" were deployed and items were stored. Both despanwed once the event triggered its next run. Items stored were lost along with the deployed tents.