First I think it was added in August, not March. There are two possible problems. One the zwave binding may predate when the device was added. Second as a battery device, it may need to be rewoken a number of times to be configured with channels.
On the openhab-cli console run bundle:list -s and look for the date on the zwave binding. If before August, need to update. I think you can add to the latest build in addons, but may need to update Xstream
Bob
Edit: the other option is to upgrade to 3.2 milestone 4. That should cover all the bases.