Tricky, but not impossible...
Position your hands on the keyboard so your middle fingers are on the "E" key (Left Hand) and the "I" Key (Right Hand).
Your index fingers should then be positioned on the ""D" Key (Left Hand), and the ""K" Key (Right Hand).
This will give you basic Up/Down movement. Left and Right become a bit tricker, as you need to use "S" / "F", and "J" / "L" for Left and Right movement (all by default)
Of course, the ideal solution is a dual 8-way joystick configuration... :p