If you create a bridged appearance then you should see the caller ID
You might need 2 buttons so that you can see a second call as well should there be 2 simultaneous calls.
You can also use coverage appearance and simply have them ring on that button, that should also show you the caller ID of the caller.
Joe
FHandw, ACSS, ACIS
"Dew knot truss yore Spell Cheque