It was a surprise to me, but the Manual for Autohelm 3000
indicates it can be controlled by radio navigation
device through a standard NMEA 0183 plug
So save your planned course on your nav equipment
and Auto3000 is supposed to follow the nav equipment
all the way home.
I have not tried this yet since I just read the old manual, throughly for the first time.
Perhaps it will help in some way.