Press F, the boxes should become big on the botton of the screen, then use your weapon selection keys ( 1, 2, 3, 4, 5, 6 ) to select a force power.

rubat that doesnt work i just tried and im having the same problem, please look into this if you can.

Yes, i also used F and pressed the different numbered keys on my numpad and on the other number keys, i tried using a few methods i saw in the forums, but to no luck. it doesn't work in single or multiplayer