I think the ps3 only recognizes the keyboard as a means to type, not to control your character. You can Technically map spells, but it won't be the exact same as the pc.

Under keybind, go to > Controller > Set L2 to a key, R2 to a key, and the dpad buttons and triangle circle square x to the keys you would use to activate skills (like numbers 1-8.)

To use them, you'd have to hold down either the key for L2 or the key for R2 while pressing the skill key, much like how you would hold down L2 or R2 before pressing dpad or triangle x circle square. You can't change the cross hotbar to the pc one due to the Ps3 memory limitations =( They might be able to do this on the Ps4 though.