http://www.rcuniverse.com/product_gu...fm?kit_id=1077

First I'd recommend using a single servo as manufactured.

If determined to go ahead I'd probably cut holes as needed to fit the servos. Then I'd cut a couple of hardwood or plywood pieces for each end of the servo to mount to. Dig out a small area to fit these pieces into the wing and epoxy them in place. If wing is solid foam you will need to make an internal path to run your wiring.