Setting it to another object wouldn't work, as the UI object's actual position is always going to be off, owing to the UI layer's parallax property.
Assuming that you have your UI object in the top left corner, you can set the object's bullet angle to angle(Collectable.X,Collectable.Y,ViewportLeft("Game"), ViewportTop("Game")). This will just send it off to the top left corner and not, strictly speaking, to the UI object itself, but the effect is the same.