Creating a subdomain for testing purposes, as you suggest, is the only way of dealing with this particular situation.
For experienced users, this has never really been much of a problem. In fact, DreamHost allow you to create subdomains like uniquewhatever.dreamhosters.com for this reason. For beginners, however, I've always thought this was a rather clumsy way of doing things, and a failing of DreamHost.
Simon Jessey | Keystone Websites
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