I to lazy to open VHE but im pretty sure what Jokerboy said is correct.
But if you have the fgd and all that crap set up, then just make a box with the Trigger Texture, and when you have it selected, press (Alt) and (t). That will make it into a world object rather then a solid now, and then you only have to scroll through the list looking for somthing like Trigger_Rescue, or somthing along the lines of that name.