Adding wire bonds to bottom side die pins

Hi,

are there any special pitfalls when using bottom (back) side die pins? I have no problems to add wires from die top side to bondpads on the top side (WB1 in attached picture). But when I try to add a wire bond from a bottom side die pin the wire connects to the top side of the die (WB2 in attached picture). I am using Expedition 7.9.4.