I have a MS Lync account with phone service. It would be great to use my Obi to talk through Lync.
I'm looking over their system. It seems unlikely from what I see so far. It might be possible if you were running your own Lync server.
Who actually provides your Lync phone service? This can be an outside company.
Are you using your own Domain name?
I found a reference to the following
sipdir.online.lync.com
It's possible but I think unlikely that you can register the Obi using that address. I think there is some additional behind the scenes vudu going on.
http://onlinehelp.microsoft.com/en-us/office365-enterprises/hh416761.aspx