No SignalK key for NMEA RMB data

[affinite]

OP 0.9 Noobs 
Im trying to get signalK output for Distance and Bearing to waypoint for my autopilot and for NodeRed dashboard
My AP wants to see the NMEA NMEA "RMB" sentence and (with an OCPN route active) I can see RMB being generated.
It seems that processing RMB into a SignalK message isnt an "out of the box" feature as RMB doesnt appear in the SignalK diagnostic page

so Im trying to set it up using the NMEA 0183 generator tool from menu.
My problem is that i cant find a suitable SignalK key to map to RMB.
Am I just getting ahead of development or have I missed something ?

Thanks
Steve

[fbeauche]

I'm interested in this as well... not for autopilot but at leas to show on a NodeRed Dashboard.

From what i understand form the spec (http://signalk.org/specification/master/keys/) it should be navigation.courseRhumbline.nextPoint.bearingTrue but i'm not sure ...