Slum, did you invite them to the group? Or to wave? Because martinszeme has a wave account, but didn't have the polycount wave. Kovac doesn't have a wave account at all ;)
Mr Knubben sorted me out with one, but I've got no invites with mine. I'm not sure if some accounts come with a few invites, or the invites appear after your account has been active for a while. If I get some I'll post here.