I just rolled it out on our network with ZenWorks. I used snAppShot and installed Phone Manager. I created the Zen app and went in to start picking apart the registry changes. I got rid of the obvious ones to leave out (IE History, etc) and removed the user name that I had selected during the snappshot process. I left the IP of the phone system in the registry and saved out the application.
I couldn't think of any way it would be possible to pre-emptively select a username. How would it know!? So, I settled for automating the program itself, and instructed the users how to get past the first error and select their user from the pulldown box. This seemed to work okay, because I didn't field any helpdesk calls regarding installation problems.
Hope this helps you. It sure beats visiting each PC.