I don't know if you have done this because I cannot see the code.
If you look at the arduino page for using multiple shift registers it says to connect to the last pin ex dF' and connect that to the data input on the next register. What it then says is you need to send a shift out twice for each device. So What you need to do is shift out twice. The first shift out goes to the furthest register and so on. BUT only if you send another shiftout before flipping the latchPin. Its like the overload, so if you push data twice the first is sent out the overload to the next dataPin if connected 
Sorry if that doesnt make sense!