Yeah I came across the same prob, found that remapping the pitch up and down controls manually in the aircraft control tab works fine.
change pitch up, to mouse down
vice versa, this will keep your other mouselooks the same but change the aircraft one, tick box would have been nice but this works.
check the arma2 troubleshooting wiki for more:
http://community.bistudio.com/wiki/ArmA:_Troubleshooting#Controls
Good luck!