M19 spindle orientation on slant pro lathe

Is anyone able to make m19 spindle orientation work on the slant pro 15 lathe?  The lathe has an encoder and I believe the mx machines use m19 to rotate the spindle for tool changes.

This would be a good feature for broaching on the lathe even if I need to lock the spindle after each rotation.

I'm also curious about using M19 for broaching on a 3 axis mill running a servo spindle. Seems like it should work but not sure how to execute.