Noob help: Creating new item with Wild Surge "Squirrels... Everywhere squirrels!"?

I'm a noob blundering my way through learning how to create new BG EE items. Is there a way to add an Effect to an item (weapon) so that on a successful hit, it has a 10% chance (or whatever) of triggering the "Squirrels... Everywhere squirrels!" (a roll of a 2) outcome from the Wild Surge table?