props->tie("position/x-offset",
SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getXOffset, &FGAIBase::setXoffset));
props->tie("position/y-offset",
props->tie("position/x-offset",
SGRawValueMethods<FGAIBase,double>(*this, &FGAIBase::_getXOffset, &FGAIBase::setXoffset));
props->tie("position/y-offset",