Hi Paul,
User administration in Connections currently is a pain in the ass to pull off.
I hope this product will see the light within a few months.
http://www.timetoact.de/ttacms.nsf/id/lotus-connections-administration-toolkit-cat-en
It all looks a lot more admin friendly than all those WSadmin commands.
Did you already try to use the command with the PROF_UID or PROF_GUID values as parameters?
Regards,
Marco