Arduino Mega 2560... PWM pins 45,46,47 not working

I have almost finished constructing a 17DOF robot but cannot attach the 17th servo for the head. I'm using Adafruit 16 channel servo driver attached to Arduino Mega 2560.
How can I add one extra servo without attaching an extra shield? I have tried using pin 45 on the Mega controller but cannot get it to work with PWM control.
The servos are LDX-218 which only seem to work with PWM values not with Servo.h

Mach_07:
I have tried using pin 45 on the Mega controller but cannot get it to work with PWM control.
The servos are LDX-218 which only seem to work with PWM values not with Servo.h

Have you tried Servo.h?

This spec sure look like standard PPM offered by Servo.h

Control Specifications:
Control Method: PWM
Pulse Width: 500~2500
Duty Ratio: 0.5ms~2.5ms
Pulse Period: 20ms