Get anonymous profile

Hello,
I am working with an ASP.NET MVC Web Application and I am using the following custom profile provider:
http://weblogs.asp.net/jgalloway/archive/2008/01/19/writing-a-custom-asp-net-profile-class.aspx
One of the properties is allowed to anonymous users.
How can I get the profile of an anonymous user? They don't have a username, right?
I am a little bit lost on this.

Thanks,
Miguel

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