I am planning on adding a 4-port Partner VM system to an existing Partner ACS unit. My question is, how do callers get to a particular extension? Do all calls have to go to VM first, get a directory, then caller can press directory extension, caller gets routed to phone, user can either pick up call from ringing phone or if user is not there, does caller automatically get routed back to VM? Does the Partner ACS system allow DID extensions, so that caller can dial directly to phone before accessing a directory through the VM system?