How to use registration inputs on a Kinetix servo?

I am working with a Kinetix 5500 servo drive with a rotational actuator to locate a keyway on a shaft. The shaft will rotate, and a laser sensor will detect the height difference when the keyway passes in front of the sensor. I need to record the position of the keyway so I can orient it to a known position.

The laser sensor will be wired to Registration Input 1 (see pages 62 and 65 of user manual above), to capture the position of the servo more accurately than using a sensor wired in to the PLC's I/O.

I have been able to find little information about how to actually use a registration input in my PLC program. I know there is some sequence that is required to arm the registration input to look for a transition, and then grab the saved servo position from the drive.

How does this process work? Is there documentation from Rockwell that I'm not finding? (I found a programming manual for PowerFlex, but not Kinetix)

Additional information: the PLC is an AB ControlLogix, and the drive is connected via Ethernet. I am familiar with setting up, tuning, and issuing Motion Direct commands for Kinetix drives.

Related nonexistent tags: Allen-Bradley, Kinetix, ControlLogix

Another use for this input is in conjunction with the MAR (Motion Arm Registration) instruction. This is done when you want to control the position of a continually rotating axis relative to something else. When registration is armed, the drive watches for the next transition of the registration input and then logs the position at that point in the .Registration1Position field in the Axis Tag structure. You can use this value to speed up or slow down the axis to maintain the relative position you are trying to achieve. The configuration for this is done right on the MAR instruction; you select which input number to use (1=Registration Input 1), and what type of Trigger Condition you want to look for (0 = trigger on positive transition, 1 = trigger on negative transition).