Yes, a few people asked for wiring help with the humidifiers, so I told the factory about the lame wiring instructions and they sent me their wiring book. They think their wiring diagrams are the 'cat's meow' but they are sorely in need of a good technical writing revision to help their installers and customers. The booklet doesn't help an experienced electrical engineering control specialist get a hint about how to wire it.
If they simply said that the 115-volt plug that dangles out of the humidifier provides all the power, both 115-volt for the fan and 24 volts for the humidistat and other control switches, the installer would be well-advised and could go from there. For some reason, they think it is important to leave that out. They used the 115-volt plug to provide fan power and transformer power in the control board so the humidifier can act on its own independently of the furnace fan (if you don't use the 50 relay, so the furnace fan wouldn't have to be powered for the humidifier to work.)
The additional information on the diagram about the 24-volts from the furnace power board is unnecessary and could prove harmful to the 700 model.
The transformer on the control board in the humidifier provides the 24 volts for the fan relay on the board and the water solenoid. The humidistat and outdoor switch and 50 fan relay just break the path of the wire between the transformer and the fan relay and solenoid. The terminal strip saves using wire nuts. I don't have the humidifier, but the people who wired the unit this way are satisfied as they tell me.