Servo control from fsia6b
 

Hi,
I am trying to control a servo directly from the fsia6b receiver. i have a fsi6 transmitter which has a pwm range of about 1000-2000us. I am using a tower-pro sg90.
With the servo connected to chanel 1, this is connected to the horizontal gimbal of the right stick.
When i move the stick to the right the servo goes from central to +90 when the stick goes from the central position to the right.
When i move the stick to the left the servo goes from central to -90, when the stick only goes from the central position to halfway to the left.
Why is this happening?
Thanks