Yeah look under your keybinds in WoW and find the "Interact with Target" keybind and assign a key to it. You will also need to have "click to move" enabled under mouse or camera settings, forget which.

Not sure how the new Pwnboxer works, havent used it since the new version. But if they dont have auto-assist keys then you will have to have a /assist macro to assist your leader before pressing the IwT keybind.