Well, I believe MCServer defines a block face as what direction the face is facing, but arrows and its block tracers use what direction the player is facing if they look directly at the face. Therefore, AddFaceDirection works without the invert bool (which arrows should normally require), but not for top or bottom faces.

Because of this, and the fact that I cannot understand anything bar basics with arrows (more comments xoft! :P), I don't know how to fix *properly*.