Well the datasheet says that it is a 4 turn servo. And as a servo it's position commands span 1000 usec to 2000 usec for full travel. So you are probably much better off using the servo library's writeMicroseconds commands rather then using the 0-180 degree commands. Then you can map the servos 0-1,440 degrees of travel to 1000 to 2000 usecs command values. Map is a very useful function to make such conversions simple.
http://arduino.cc/en/Reference/Map
Also I think you would be better off using the servo library that ships standard with the latest arduino IDE. Although I am not familiar with the one you linked to.
Good luck;
Lefty