Another method, if you have the vertical room to work with, is to install the mounting plate so that only the output shaft and servo wheel are outside the covering. Then, install the servo, without a wheel, and cover right over it. Finally, cut a small X over the top of the output shaft and shrink the covering followed by installing the servo wheel. Looks good and doesn't require 8 screws, 4 for the servo and 4 for the hatch. The only downside is you have to cut the covering if you ever decide to remove the servo.

John