autoland trouble

it's a week that I try to solve my problem without success:half of the times I try to land in a full autoland configuration,just a little bit before touching, the autopilot disconnects and the trim starts to work (I think it tries to mantain the glideslope...).I read a post few days ago about this problem; the user said that perhaps the problem was the imported flight plan...I tried making directly the flight plan in the FMC but it did'nt solve;...naturally, the setting of all the parameters for the autoland is right when the autopilot disconnection happens....soI hope that someone could help me!thank you very much albertoPS: is not possible to to set the gear in the off position from the virtual cockpit?