We have recently purchased a Mitel PBX phone system for the entire company and I was tasked to push down the Xarios Phone Manager Software with the K1000. I did this using the following:

phonemanager.msi /q /norestart /i

This seemed to work for me but worst case scenario would have been to use the MSI Install wizard via a script. FYI - A pre-requesit for this software is to have DotNet 4.0 Installed on all client computers.