Another approach is to create new instances of the WebSphere entities.
Use the adminclient.sh to start the WebSphere console.
Create a new virtual host instance and a new Application Server instance name.
Click the entry under Nodes (typically the host name), and select Regen WebServer Plugin.
This process saves the new entries into the plugin configuration file, which the installer checks for the legal names.
Return to the installer and enter the values you just created.