Given that there have been a number of enhancements since the NextGen user's manual was last updated, I'm wondering whether "motor open" detection and a corresponding flag might be among the new additions.
I have added this functionality (in my script) using Allegro current sensors and send the appropriate messages via RawCAN over my multi-node CAN network. It works, but it's certainly more awkward than having the firmware do the detecting.
Ciao,
Lenny