This is correct. You have to select the com port at bottom of the zwave device template.
I found the easiest way was to add the device in web admin before plugging the zwave dongle in. Looking what com ports were there. Then plug the zwave in, do a quick reload router and look again. The com port that has been added is the zwave. In my case this showed ac pci0000:00/0000:00:16.0+3.
Not sure if this is a step that is only needed in Dianemo or if it is same in linuxmce?
Perhaps Andrew could comment on this. If it is not just Dianemo maybe someone could update the wiki.