Depending on how servos are mounted in the plane itself, you may need to reverse a servo or two in your setup, this happens in any plane.
Did you try reversing a servo?
This does happen, I actually wrote an FAQ for our website regarding this problem:
http://www.futaba-rc.com/faq/faq-10c-2_4ghz-q316.html
Sincerely,
Krysta
Product Development & Support Specialist
Futaba Service Center USA
[email protected]