Update on use of HDT message as source of heading (replacing compass)

As far as I know, arducopter 4.0 supports NMEA HDT message as input for heading information, allowing for the compasses to be disabled (this is useful when using drones indoors, as compass readings are erratic and unaccurate).
I plan to use external sensors (in my case Marvelmind paired beacons) to provide precise location and heading information to Arducopter, using thye GPS port of pixhawk and NMEA standard messages. I will dissable compass and fly the drone indoors in autonomous modes.
Can anyone confirm if this message is supported and if this strategy to use it dissabling compass can work?