I think you can take out two jumpers (D4 and D5) and hardwire them to other digital pins. D4 is for direction control, so any digital pin will do, but for speed you need to pick any other free PWM capable pin.
And you should also consider swapping D6 with some other PWM signal that is free and uses the same frequency divider as the other one, and change it to at least ...was 32kHz? You get quieter motor control under full speed, and more torque as well...?
This seems to be newer version of Romeo than ours, older can't take shields.
Links would be nice, but somehow I managed to find these parts... PaulS... 
Cheers,
Kari