We are the sole administrator for Lync and all our users are using Attendee clients. We have successfully tested on demand meeting rooms such as "https://meet.lync.com/XXXCOMPANY/administrator/A1B2D3D4" but these meeting links are not permanent and expire usually a day or two. What we would like, is to have a meeting link, preferably customizable, that do not expire (permanent) just like in LM2007.
Ideally, we would like to have control over as and when to activate a meeting link. So that users can use the same credentials to go into the meeting room. Once a meeting link is "activated", anyone who knows of the URL can go in via Attendee clients. After a meeting, the meeting room will be disabled until we reactivated it again.
As far as I know this is how Lync meeting work already. They don't expire as long as you have the URL. The only thing is that others connecting to the meeting as a guest will need the meeting's creator to allow them into the meeting.
However this could be because we are running Lync 2010. Our URL's are a little different, they have the format: "https ://meet. XXXCOMPANY .com/administrator/A1B2D3D4"