I just did the same for one of our customers. He didn't want to upgrade; just get a new server. Here's almost an foolproof way to move to a new server, assuming old and new Sage is identical.:
1. Install Sage, SP, Server Config, and anything else you need on the new server, using the same paths, same port number as current Sage. Run WKsetup, make sure it works. Basically, it's a proper install that will write to the registry.
2. On the new server, change the name of the MAS90 directory that you just installed (Let's call it MAS90NewServer).
3. Grab the MAS90 directory from the old server and put it where it now belongs on the new server.
4. In this MAS90 folder, rename the Unistall and UninstallInformation folders (you may have only one).
5. Copy the Uninstall and Uninstall Information folders from the MAS90NewServer and paste it into the MAS90 folder.
6. Remember to change the PaperlessOffice path names.