Only the new 7xxx series servos will have the overload protection function which is why you can't set anything with your servo.
The number to teh left of the : is what the servo is currently set for in terms of speed. A higher number is faster. The number to teh right of the : is what you want to set the servo to so when you have it selected to teh number you want, press the "M" button to store that setting and you will see the number to the left of the: change to what you had selected to the right of the :.