The Z240 SFF blue front USB3 2x10 header pinout is the same as the Z420 front USB3 2x10 header, as SDH pointed out.
This USB3 pinout uses the Intel-specified header and pinout. The only difference is pin10, which HP front IO USB3 cable grounds to tell the motherboard that the cable is connected. Others might disconnect this pin, or use it for a port power overcurrent condition, but I do not really know what other manufacturers choose to do with it.
The standard pinout is why the aftermarket media card readers work in this header. However, with a cable plugged into the header, it does not allow jumpering pin 10 to ground to fake the system into thinking the front IO cable is connected. (I cannot recommend soldering wires to the motherboard to prevent this error message.)
