Poring users to another Proxy Server

Hi, We are on microsoft NT Doamin & planning to upgrade our existing Proxy Server & instal a fater P-III with the same user rights etc. as of now. Is there a software by which I can port all my exising users from one Proxy Server to another Proxy, with all the user rights that I have currently given for the users (PO3, SMTP, HTTPS etc.) comes into the other one as it is. There is however an option for taking backup of the server, but with this new server the name of proxy is changed. Anyone knows about this ??
Akash