OK, I'll chime in with my $0.02...I had a gut feeling when this started that things were going to turn out like this. But I just can't sit by and watch anymore. One of the reasons I took up this hobby was the camaraderie between people. I receive assistance all the time from people at the field, and in turn I lend assistance where possible. That's what makes this hobby special.
Anyway, the pics below are of a 4* 60 wing and the wing-mounted aileron servo. I suspect that this design will also work in the 4* 40 wing, and I believe that's what RCKen, bruce, MinnFlyer and everyone else is talking about. Sometimes a pic is worth a 1,000 words.
The first pic shows the left-hand aileron servo from the top of the wing. The servo is mounted to 2 small blocks of balsa first (using the supplied screws and grommets), then the 2 blocks are glued to the servo hatch cover (with is lite plywood - 1/16" I believe).
The second pic shows the overal position of the aileron servo in relation to the wing. It also shows my messing building area -- but that's a different story!
The third pic shows the bottom side of the wing and how the hatch is fastened to the wing. When the hatch is removed, it sits on 2 rails (one on the left side and one on the right side). These 2 rails are glued to the wing rib before putting the hatch in place. The rails provide support as well as a place to fasten the hatch cover to, as well as keeping everything nice and flush. You cover the hatch and the wing separately, so if you have trouble with a servo, you don't have to cut the covering to access it. Also shown in this pic is the paper servo lead tube in which you run the servo wire back to the fuselage.
The fourth pic shows what I described in the third pic about how the servo is mounted to the hatch. There is a small gap between the servo itself and the servo hatch. This gap prevents vibration of the airframe from transferring to the servo. There should be no direct contact between the servo and anything else. The job of the rubber grommets are to isolate and insulate the servo from vibration.
I hope this helps. Even though you're excited about this build, I highly suggest you heed everyone's advice and SLOW DOWN! When I first got my kit, I wanted to dive right in and start the construction. But I've taken things really slow (going on 4 months now) and have caught myself several times before I made a costly mistake. I've screwed up several times as well, but by taking extra time and going slow, you'll have a chance to catch your mistakes now before they become real evident in the air.