Simulating servo in SITL gazebo

I am trying to simulate a VTOL tiltrotor in gazebo.
I have used the standard_vtol as a template and configured the init file.
I am unable to provide the required angle of tilt to the motors as there is no servo plugin in SITL_gazebo.
Can anyone help me to setup the tilt servo in sitl gazebo?

I used a scale of 1.57 (pi/2) and now it works as expected.
Another problem I am facing is with control of motors.
I inserted an extra frame called tilt_servo which is connected to the base_link and then attached the rotor_0 frame to it. By doing this the tilt_servo is working properly but the rotor is not spinning.
When I attach the rotor to base_link or I disable the tilt_servo, the rotor starts rotating as expected.
Any suggestions on how to solve this?

Hey, have you managed to overcome this?