Installation Problem

[_InFeCtOr]

I am installing ISPConfig on a fedora 4 server for a client. However, I have ran into a problem that I see no sensible solution for. The client will be hosting site site from said server, using ISPConfig. However, the installation wants to know the hostname that it will be running on. This host obviously doesn't exist because the client will also be hosting his own DNS. He needs ISPConfig setup to be able to configure this, but the setup process fails because the specified host doesn't exist. Can someone please tell me the solution to this, as I don't see it