I just discovered there is also a module which integrates to zwave, but it’s twice as expensive! See the List of shops that sell this.
The OTGW-binding I use is supposedly an experimental one, but the current version, 0.8 is working very well. See the OTG-thread.
I did have to change some things in the items they suggest and also I changed the way the room temperature setpoint is handled which I described in post 108 of the above topic.