Trapping Nonvisible Containers with DLTCP

I've been trying to place a resetting trap on a "nonvisible" container I created at the plateau level of the Ulcaster School (AR3900), but nothing I've done seems to work so far. At first I thought it was an issue with triggering the Call Lightning trap, but I've tried other trap scripts (Flame Strike and Lightning Bolt) and they're not being triggered either. Here's a screenshot of the editing page:



Does anyone have any thoughts on what might be causing it to not trigger?